I was told by my mechanic not to use high idle on my truck in the cold, He said that there have over 180 failures in Alberta this week alone. :eek:

Now we are having some severe cold -30 to -48 at night but this isn't my trucks first cold spell and it has never had a problem before. Is this just rumour or is there some truth to it, and if so does it effect all Ally's or just the 6 speed's ?

there is truth to this rumour. i got a letter a year ago sayin not to use the high idle if the temp was below-35.

Okay this is likely a stupid question but why would the truck idling at a higher level while sitting in park affect the transmission?

because the fluid is so thick that the trans pump could cavitate.

Just let the truck idle for a few minutes to get the fluid moving, then you can use high idle.

It's off topic, but nice FJ varty yo

because the fluid is so thick that the trans pump could cavitate.

Just let the truck idle for a few minutes to get the fluid moving, then you can use high idle.


I guess the colder it gets the sooner the high idle must kick in. Right now the high idle on my truck doesn't start until about 3 minutes after it has been started. But coldest it's been here is around -15F.

If you are talking about the one that warms the truck up faster and not the power take off option then mine already waits a couple of minutes or so before it revs up. Granted we have only been down to single digits and low teens so maybe it would behave differently below zero?

The 6 speeds (2006 and later) have a park idle warm up mode. In Park/neutral the trans locks to load up the engine to create heat. At extreme cold temps, the thick ATF may not be flowing through the trans cooler fast enough for high idle. The new Allison brochure says to use TranSynd in trucks that expect to see -40 and below temps.

It's off topic, but nice FJ varty yo

thanks!!! its my toy and i wouldnt sell it for anything. i havent drivin it since august:(

because the fluid is so thick that the trans pump could cavitate.

Just let the truck idle for a few minutes to get the fluid moving, then you can use high idle.

Good to know... what fails inside?

The torque converter turns blue and stinks like you wouldn't believe. we've got one guy in the shop doing converters including complete disassembly and cleaning of the whole trans and I start doing them on tuesday. we have approx 35 on the lot needing torques and the other dealer in town is about the same. there is a reprogram for the tcm that should be done to prevent this from happening. we are also flushing the cooler system at the same time. Grande Prairie alberta

Just buy one of those magnetic oil pan heater mats and stick it to the tranny pan instead.

in the 06 to 08 gm they us dextron 6 it wontflow at - 40 my oil burnt 2 days ago changed filters put amsoil in 3 weeks to get in to get fixed still shifts hope it lasts

sounds like a pretty bad flaw in this "wonderful" allison.
to bad, I'm starting to like this transmission (for an auto)

i just dont use my high idle first thing in the morning. once it warms up a little i switch it back on. uses a ton of fuel with it on in the morning anyways

The 6 speeds (2006 and later) have a park idle warm up mode. In Park/neutral the trans locks to load up the engine to create heat. At extreme cold temps, the thick ATF may not be flowing through the trans cooler fast enough for high idle. The new Allison brochure says to use TranSynd in trucks that expect to see -40 and below temps.


SO this issue is only in the 06 and later 6 speeds then ?

this makes no sence at all....

The 6 speeds (2006 and later) have a park idle warm up mode. In Park/neutral the trans locks to load up the engine to create heat. At extreme cold temps, the thick ATF may not be flowing through the trans cooler fast enough for high idle. The new Allison brochure says to use TranSynd in trucks that expect to see -40 and below temps.

What locks, exactly? I don't know of anything that could lock with the trans in park (same as neutral) that would cause a large enough load to make any difference. Locking the T/C clutch would be just the same as lifting your foot off the clutch with a manual trans in neutral. Could you expand on this a little?

What locks, exactly? I don't know of anything that could lock with the trans in park (same as neutral) that would cause a large enough load to make any difference. Locking the T/C clutch would be just the same as lifting your foot off the clutch with a manual trans in neutral. Could you expand on this a little?
The way I've heard it is it engages third and fourth with it still in park.

does this affect the older allys? I was gettin ready to install high idle but after reading this im a little reluctant to do it?

I guess the colder it gets the sooner the high idle must kick in. Right now the high idle on my truck doesn't start until about 3 minutes after it has been started. But coldest it's been here is around -15F.

:exactly: Mine takes 3-4 minutes before the high idle kicks in. Is this enough time to get the fluid warm enough to flow?

I guess the colder it gets the sooner the high idle must kick in. Right now the high idle on my truck doesn't start until about 3 minutes after it has been started. But coldest it's been here is around -15F.

I think it might be the oppisite of that. We have had some pretty cold mornings around here the last few weeks, down between -9* to 5* and mine will stay in the normal idle for at least 2-3 minutes before it kicks in to the "high idle mode". Makes me feel a little better then if it were to start right up on high as soon as you started it up. Though we had a couple of warmer mornings about a month back, right after I got my truck, and with it being about 40* or warmer, the high idle wouldn't kick in.

this a programming issue with the 06 and newer allisons. turn off your high idle and see if the local dealers will reprogram your tcm's

I just checked mine and I have leaks in the driveway with only 32,000kms on it. I will make an appointment at the dealer tommorow.

wish mike l would chime in on this

don't know if its related or not, but when its really cold first thing in the morning, if I don't wait at least 5 minutes or so before I put my truck in gear the trans will vent some ATF out on the ground. Its fine after a few miles, and won't do it the rest of the day. odd, but how it behaves.

sounds like a pretty bad flaw in this "wonderful" allison.
to bad, I'm starting to like this transmission (for an auto)

do you know of anything that works well at -40*??

this can and does happen to any machine that uses oil/fluid for lubrication. Blame the fact that all oil is sludge at 40 below zero, not the trans.

^ +1

x2 Ben.

When it's -40°F, most trucking companies let their trucks idle 24-7. Be thankful your Allison equipped Duramax even starts at that temp!

.... with it being about 40* or warmer, the high idle wouldn't kick in.

The High idle only kicks in at 32°F (0°C) and below. At least thats what I remember reading somewhere.

do you know of anything that works well at -40*??

this can and does happen to any machine that uses oil/fluid for lubrication. Blame the fact that all oil is sludge at 40 below zero, not the trans.

Its hard to beat Physics you know. Use of a full synthetic Like TranSynd helps obtain flow at extreme cold temps, remember we're only talking about -40 and BELOW. Do the test yourself, pour some ATF in a jar and set it outside in below -40 temps and see what it looks like.

Also as mentioned earlier in this thread there is a cal update for the 2006 through 2008 trans that makes the warm up less aggressive and gives time for the oil in the cooler to get moving.

Even without the high idle I'd say that the truck warms up fast enough. When the temps get around the -40 mark. I would assume if someone adds a oil pad heater to the trans pan than they wouldn't have to worry about all these problems

Even without the high idle I'd say that the truck warms up fast enough. When the temps get around the -40 mark. I would assume if someone adds a oil pad heater to the trans pan than they wouldn't have to worry about all these problems

I think you might void your trans warranty if you put that heater on.

Putting on an oil pan heater on an Allison has been done for many years, I worked in Edmonton for the Detroit Allison dealer and they installed many of them. I have noticed on my truck that the idle was above normal on the mornings it is cold it's up to about 900 RPM and the shift points are higher till it warms up. PLAY SAFE!

Putting the heater on the pan can help, help get you in trouble. Sure it means the pump gets pumping oil and making pressure to apply clutches. BUT it takes a LONG time before it gets any oil moving through the coolers, the air-to-oil in particular. If you start driving, the cold air may keep the fluid solid up there.

Putting the heater on the pan can help, help get you in trouble. Sure it means the pump gets pumping oil and making pressure to apply clutches. BUT it takes a LONG time before it gets any oil moving through the coolers, the air-to-oil in particular. If you start driving, the cold air may keep the fluid solid up there.

Plus the fact that return oil from the cooler is lube for the geartrain before it drops to the sump. If you don't get that return the geartrain runs without lube which is dissaster in a short period of time.

i have yet to see a pan heater on any allison around grande prairie alberta. also haven't seen a pan heater on too many duramax pans (2-3 maybe). i personaly wouldn't put a heater on the pan. i just take it easy when it's cold out.

So is the High Idle really the root cause of the problem at -40 deg F., or is the real problem dyno ATF don't flow well at that temperature and provides inadequate lubrication.
If someone didn't High Idle and did a minimal warm-up before driving off would it be any different? As already said, -40 deg F. is frickin cold and hard on everything.
For me, synthetic ATF would be a definate, and waiting to High Idle 3-5 minutes after start-upand then High Idle for 5-10 minutes before driving to keep load on tranny at a minimum until ATF warms.
Something not mentioned, would be to use engine coolant heater full time whenever shutdown. The ATF will not warm up until after the engine coolant warms up.

it cooks the torque and wrecks the pump mine is number 27 at the gm dealer in fort saint john bc 3 weeks to get parts week or 2 after that the dextron 6 jells at 40 below

I was told by my mechanic not to use high idle on my truck in the cold, He said that there have over 180 failures in Alberta this week alone. :eek:

Now we are having some severe cold -30 to -48 at night but this isn't my trucks first cold spell and it has never had a problem before. Is this just rumour or is there some truth to it, and if so does it effect all Ally's or just the 6 speed's ?

My brothers 2006 LBZ truck is in the shop for this exact problem. He warmed up his truck when it was -40C for less than 15 min, and that was it... transmission was history. He said the dealer that is repairing the problem, has a parking lot of trucks in the same situation.

I never would have thought just by warming up a vehicle you can cause a transmission failure on what we both thought were one of the best transmissions out there.

I have a 2007 LBZ, but despite being in a garage (which is slightly heated), I am hoping my truck is ok.

it cooks the torque and wrecks the pump mine is number 27 at the gm dealer in fort saint john bc 3 weeks to get parts week or 2 after that the dextron 6 jells at 40 below

FYI. Allison recommends the use of TranSynd where temps are expected to be -40 or below.

That's included in the back of the "Getting to know your Allison" brochure with the new GM trucks.

Let's make sure we're all talking the same temperature. Some are talking Fahrenheit, and some Celsius.
Luckily in this case, -40 F. = -40 C.

http://www.wbuf.noaa.gov/tempfc.htm

FYI. Allison recommends the use of TranSynd where temps are expected to be -40 or below.

That's included in the back of the "Getting to know your Allison" brochure with the new GM trucks.

Did that note come with the 2007 classics? or NBS trucks?

Thanks

After keeping my truck plugged in all night, my high idle probably comes on after 30 secs to a minute. I thought that was a little early. I usually let it warm up for approx 20 -30 minutes before driving.

This problem seems very very strange to me that GM's R&D department would not catch a problem like this. I have spots of tranny fluid on my driveway but I checked and my tranny level is fine and it doesn't smell burnt but I phoned up GM to make an appointment and they wanted the serial number to order new lines without even looking at it.

Good thing to know, but I dont seem to think I would be affected that much, living on the beach and all. Temps here rarely get lower than 28F.

Wow, just found out today that this was a problem. Only a one come in with a torque converter crapped out for same reason.... Laast week it was -38C...Red Deer AB.

So this problem only affects the 2006 and newer models? Makes me thankful that I'm already running Transynd in my truck, and also that it's a 2003. At -20C a week or so ago, I usually only let the truck low-idle for a minute before switching it to high-idle!

So this problem only affects the 2006 and newer models? Makes me thankful that I'm already running Transynd in my truck, and also that it's a 2003. At -20C a week or so ago, I usually only let the truck low-idle for a minute before switching it to high-idle!


My brother asked the dealer in Athabasca about using Transynd, and they advised against it saying that it could void warranty, despite allison recommending it.

I can't believe anyone would recommend against synthetic in a cold environment.

We were trying to find documentation from GM that they say its ok to put it in.

Here's the link... Or have the dealer go out to the glove box of one of his new trucks!
Last page, left side, at bottom of the box titled "Cold Operation"

http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA5521EN.pdf

TranSynd's GM part number: 12378515

Here's the link... Or have the dealer go out to the glove box of one of his new trucks!
Last page, left side, at bottom of the box titled "Cold Operation"

http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA5521EN.pdf

TranSynd's GM part number: 12378515

I see where ''Allison'' recommends it, but no quote from ''GM''.;)

Putting the heater on the pan can help, help get you in trouble. Sure it means the pump gets pumping oil and making pressure to apply clutches. BUT it takes a LONG time before it gets any oil moving through the coolers, the air-to-oil in particular. If you start driving, the cold air may keep the fluid solid up there.

My thoughts were to use it in combination with the engine block heater and covered radiator opening while not using the high idle, but still letting the truck ''warm up''.

Personally I think it's a design flaw that Allison/GM should make good on. So, let me get this straight, if you use a heater your warranty is void. You don't use a heater you fry your TC. Are those hit with the latter being covered? Curious on this one.


Modified... Your link is dead. Here is another (scroll to the bottom of the page)... http://www.csgnetwork.com/tempconvjava.html

I see where ''Allison'' recommends it, but no quote from ''GM''.;)

This is the brochure that GM approved and includes with the pickups.
GM has TranSynd in their Service Parts system.

As for using a heater, it allows you to operate the transmission when it would otherwise not function. If GM does not test their truck with heaters installed, you may get a different result (overheated TC) than they did in testing.

So the TCM takes temperature readings from the tranny and is it's own system, much like the ECM monitors temperature and controls the engine?

The trans temperature read by the TCM and controlling its behavior is in the pressure switch module on the bottom of the valve body in the trans sump. This is what is shown on the dash as well. The heater will fool this reading at extreme cold temps.

Went to the stealer today and I was informed of the problem. They said it's urgent, but I can't get in until the end of the month. They said they have to reflash the TCM or something like that. Does anyone know exactly what the reflash will do or what it will change? Thanks.

The trans temperature read by the TCM and controlling its behavior is in the pressure switch module on the bottom of the valve body in the trans sump. This is what is shown on the dash as well. The heater will fool this reading at extreme cold temps.

Understood... There should be a thermostatically controlled bypass when temps are that cold IMO, circulating little or no fluid through the cooler until a certain temperature.

Went to the stealer today and I was informed of the problem. They said it's urgent, but I can't get in until the end of the month. They said they have to reflash the TCM or something like that. Does anyone know exactly what the reflash will do or what it will change? Thanks.

It will cause the warmup mode to cycle on and off (a reduced duty cycle).

If you want to be sure not to overheat your truck, don't start it in -40 or below weather. If you have to use your truck, then don't select high idle and don't allow it to idle more than 5 minutes to warmup.

I do too. Mine has been in the garage since dec 1st and wont come out until late March.:chevy:


wish mike l would chime in on this

I do too. Mine has been in the garage since dec 1st and wont come out until late March.:chevy:

I haven't chimed in very much on this subject because you guys are in good hands with Crafty1. This man knows his Allisons and I trust everything he says and so should you guys. :D I am following this thread.

It will cause the warmup mode to cycle on and off (a reduced duty cycle).

If you want to be sure not to overheat your truck, don't start it in -40 or below weather. If you have to use your truck, then don't select high idle and don't allow it to idle more than 5 minutes to warmup.

Obviously this is a bit of a redundant statement! The tempature should not make a difference whether or not we can start our trucks, let alone run them at all! Some of use live in places where it gets bloody cold, but we still have to go into town or go to work... life goes on.

I do too. Mine has been in the garage since dec 1st and wont come out until late March.:chevy:

Holy cow.. your transmission is toast and its in the shop from Dec 1 to March 2008? Serious?

So I go to work for few days and look at all the reading I have to do. :D

Well I have switched to transynd several years ago and have a manual high idle so it seems I should be OK.

I just read through six pages. I think my head is going to explode. This entire subject makes me upset. I can't believe that these events lead to transmission failures. When explained you can see why it happens (this site rocks!). Looks like GM goofed again.

Is it accurate to say that if it never really gets to cold (say under -10F)that High idle is o.k.? I love the high idle feature. My truck high idles about 15 seconds after startup when the ambient temp is below 30F or so.

Holy cow.. your transmission is toast and its in the shop from Dec 1 to March 2008? Serious?

My truck is sitting in my garage until march when all the salt and snow are gone from the area. I hopeing it wont get caught out in the rain much either.

I would have to call BS on this . I worked at a Detroit Allison dealership for 10 years in Edmonton and we never had ant problems with transmissions in the winter. Unless you are stupid There are thousands of school Buses that use Allison's and never have a problem . Before I bought this truck I worked for a Freightliner Dealership and I checked they had ONE note ONE failure on a 1000 series transmission in the last few years. At 40 below ATF is very thick it will not pore out of a can. I still call BS on this kind of talk!

on my fourth torque converter/pump replacement in 2007 and 2008 gmc this week. started repairing the allisons on tuesday. I'll try to post some pics in the next day or so. so far we have repaired 11 allisons in the last 5 working days between two of us at the dealership I work at. Take them out tear them down. Inspect and clean all components. find one blue torque converter and one worn/loose bushing/broken pump. I'll be going thru the repair in my sleep soon.

I would have to call BS on this . I worked at a Detroit Allison dealership for 10 years in Edmonton and we never had ant problems with transmissions in the winter. Unless you are stupid There are thousands of school Buses that use Allison's and never have a problem . Before I bought this truck I worked for a Freightliner Dealership and I checked they had ONE note ONE failure on a 1000 series transmission in the last few years. At 40 below ATF is very thick it will not pore out of a can. I still call BS on this kind of talk!

I wouldn't be so quick to call BS on this unless you know the facts which obviously you don't. There is a problem here. Ford went through this a few years ago and the trans cooler was changed because of it and a few other things along with it.

is this a flow problem?,to the cooler? or the fluid being to thick to flow to the converter?

is this a flow problem?,to the cooler? or the fluid being to thick to flow to the converter?

First thing I would do is change to synthetic fluid as Crafty1 suggested; that is a must. I was asked today how my '06 cooler flowed in -45F and I did not have an answer. I will see if I can get some help from some knowledgable people and test it. I know it outflows the factory cooler big time but don't know what it will do in this kind of environment.

I would have to call BS on this . I worked at a Detroit Allison dealership for 10 years in Edmonton and we never had ant problems with transmissions in the winter. Unless you are stupid There are thousands of school Buses that use Allison's and never have a problem . Before I bought this truck I worked for a Freightliner Dealership and I checked they had ONE note ONE failure on a 1000 series transmission in the last few years. At 40 below ATF is very thick it will not pore out of a can. I still call BS on this kind of talk!

You just shot yourself in the foot while putting your gun back in its holster. If ATF is like Jell-o at -40 F how well do you expect it to move through the pump, if in fact it will? Not unlike untreated #2 diesel at -40 F, it'll just sit there in the tank like Jell-O too. I played with some once...its just the same as the kind you can eat.:p:

I would have to call BS on this . I worked at a Detroit Allison dealership for 10 years in Edmonton and we never had ant problems with transmissions in the winter. Unless you are stupid There are thousands of school Buses that use Allison's and never have a problem . Before I bought this truck I worked for a Freightliner Dealership and I checked they had ONE note ONE failure on a 1000 series transmission in the last few years. At 40 below ATF is very thick it will not pore out of a can. I still call BS on this kind of talk!

If this is what I hear.. that its a programming error in how the transmission operates in cold weather and with high idle on?, specific to 2006, and 2007 GM pickup trucks with Allison transmissions... who is to say that any other model had the same programming problem? (supposedly a programming modification is required to prevent).

I would be very careful before you start calling people stupid, and saying this is all BS. My brother experienced this problem, and the dealerships he brought it too has indicated its a huge problem with the recent "extreme" cold weather in Alberta that we haven't seen in years.

I think it is important that everyone remember what we are asking our vehicles to do by operating them at -40. When I was a kid no one's personal vehicle would start at -40 and few commercial vehicles or machines would move either. Even modern lubricants and machines behave strangley and suffer unusual failures in the -40s.

During the week of -40 C temperatures (without wind chill), all rural school buses were not running due to the cold.

Ya, it was just bloody downright, inhumanly, dangerously cold, lol!

All right, time to come out of retirement and set the record straight.

The problem is not with the transmission but the cooling system. As said, at -40C/F Dex 6 is as thick as jello, which prevents it from moving through the cooler lines until it warms up some. At temps of -30 (or so) and above the fluid can flow and there's no problem. So, until the fluid begins to flow the torque converter will keep churning the same fluid as it's exit to the cooler is blocked.

The problem comes when the High Idle is active and the transmission goes into a warm-up mode. What happens is that the trans module will lock up the turbine shaft in the trans by applying the C3 and C4 clutches for a brief period of time. This basically causes the TC to stall and puts a load on the engine causing it to warm-up quicker.

Now, for those of you that understand TCs, stalling them generates a lot of heat. If the cooler system is preventing flow that heat just builds inside the converter until it fails.

A software fix was released in January for 2006 through 2008 to take care of the problem. It prohibits the trans warm-up mode below certain temperatures until it's safe to do so. Trucks from 2005 or previous are not affected because they had a different cooler set-up that was less restrictive at low temperatures.

GM does recommend using Transynd in places where the temps can get to -40C/F (the pamphlet is GM's, not Allison).

Well that is the clearest post I've read today. Thanks for the info. Now all of us with 2005 and older can rest easy. Thanks again.

All right, time to come out of retirement and set the record straight.

The problem is not with the transmission but the cooling system. As said, at -40C/F Dex 6 is as thick as jello, which prevents it from moving through the cooler lines until it warms up some. At temps of -30 (or so) and above the fluid can flow and there's no problem. So, until the fluid begins to flow the torque converter will keep churning the same fluid as it's exit to the cooler is blocked.

The problem comes when the High Idle is active and the transmission goes into a warm-up mode. What happens is that the trans module will lock up the turbine shaft in the trans by applying the C3 and C4 clutches for a brief period of time. This basically causes the TC to stall and puts a load on the engine causing it to warm-up quicker.

Now, for those of you that understand TCs, stalling them generates a lot of heat. If the cooler system is preventing flow that heat just builds inside the converter until it fails.

A software fix was released in January for 2006 through 2008 to take care of the problem. It prohibits the trans warm-up mode below certain temperatures until it's safe to do so. Trucks from 2005 or previous are not affected because they had a different cooler set-up that was less restrictive at low temperatures.

GM does recommend using Transynd in places where the temps can get to -40C/F (the pamphlet is GM's, not Allison).

Well said! That's about as straight to the point as it gets...

That Was Great Post Clear Things Up Alot ,two Question Left For Me, Dose Anyone Know Where I Can Find The Tsb Because My Local Dealer Knows Nothing About The Problem And After Last Cold Snap How Do Tell If The Tranny Is Still Ok It Still Shiftand Run Ok But Can You Tell If Their Is Any Damage Down The Road Thanks

GM does recommend using Transynd in places where the temps can get to -40C/F (the pamphlet is GM's, not Allison).

Thank you for the explanation :)

Do you know where I can find information indicating that GM recommends Transynd? All I could find is where Allison recommends it.

Thank you!

All right, time to come out of retirement and set the record straight.

The problem is not with the transmission but the cooling system. As said, at -40C/F Dex 6 is as thick as jello, which prevents it from moving through the cooler lines until it warms up some. At temps of -30 (or so) and above the fluid can flow and there's no problem. So, until the fluid begins to flow the torque converter will keep churning the same fluid as it's exit to the cooler is blocked.

The problem comes when the High Idle is active and the transmission goes into a warm-up mode. What happens is that the trans module will lock up the turbine shaft in the trans by applying the C3 and C4 clutches for a brief period of time. This basically causes the TC to stall and puts a load on the engine causing it to warm-up quicker.

Now, for those of you that understand TCs, stalling them generates a lot of heat. If the cooler system is preventing flow that heat just builds inside the converter until it fails.

A software fix was released in January for 2006 through 2008 to take care of the problem. It prohibits the trans warm-up mode below certain temperatures until it's safe to do so. Trucks from 2005 or previous are not affected because they had a different cooler set-up that was less restrictive at low temperatures.

GM does recommend using Transynd in places where the temps can get to -40C/F (the pamphlet is GM's, not Allison).

So the trans efectively locks itself from turning, like when a manny is stuck in 2 gears at once? makes sense, Now I understand! and I agree with the Jell-O statement, it won't pump well in that state! LOL:D

So the trans efectively locks itself from turning, like when a manny is stuck in 2 gears at once? makes sense, Now I understand! and I agree with the Jell-O statement, it won't pump well in that state! LOL:D

It pumps just fine in that state. The fluid and the cooler are the problem, not the Alli.

Thank you for the explanation :)

Do you know where I can find information indicating that GM recommends Transynd? All I could find is where Allison recommends it.

Thank you!

Since Allison was a division of GM (at least til last summer before GM sold it), wouldn't GM back what Allison was recommending? I can't see how a synthetic like Transynd would not be recommended. Just thinkin' out loud.

Makes sense!

Since Allison was a division of GM (at least til last summer before GM sold it), wouldn't GM back what Allison was recommending? I can't see how a synthetic like Transynd would not be recommended. Just thinkin' out loud.

I agree.. my brother who has the situation where his 1 year old truck transmission needs replacement due to the cold, etc. It is at the dealer in Athabasca (Alberta) and they are not recommending using transynd mentioning something about warranty and that the advantages did not make it worth the switch. Therefore, we wanted to find something from GM (not allison) that says transynd is ok and recommend for extreme cold temps. Since they are replacing his transmission, this is the time to have the fluid switch done for him.

I have a 6 month old truck that I want to do the switch as well, but I have to do it gradually since you can only drain 1/2 of what is in the transmission at once. Either way I want to be sure I won't be hassled by GM if I encounter transmission problems, and need warranty work.

As I've posted elsewhere in relation to a heating problem with my Allison, both Chevy and Allison told me to put Transynd in it — said it is superior to the Dex stuff. In fact, both noted that the same transmission in GM medium duty trucks, school buses, etc. comes with Transynd. If anyone knows of a warranty hassle due to the use of Transynd, please post it. So far in this forum, I have never run across such an issue.

TranSynd will never be a warranty issue with GM.

wow long thread i'm never in weather that cold but is it safe to use the hi idle in temps around 10-20 f above 0

thanks!!! its my toy and i wouldnt sell it for anything. i havent drivin it since august:(

I wouldn't drive it either with the top off after August!

Nice FJ!!

It pumps just fine in that state. The fluid and the cooler are the problem, not the Alli.

Doesn't the fluid need to move through the system to be "pumped"? I understood that to be the deffinition of pumping.:rolleyes:

I wouldn't drive it either with the top off after August!

Nice FJ!!

ive just been too freakin busy!. last time i got it so stuck i had to come home to get the duramax to pull it out! good thing i was really close to home

I looked under my truck after reading this thread and found transmission oil leaking from somewhere. I think it might have blown out from the tranny dipstick as it has an oily film on it and has collected dirt on it and I do not remember it being that way before. I only have 30,000 kms on the truck so far. So I pulled the dipstick out and the oil level is okay and it doesn't smell burnt.

I phoned to my GM dealer and they ordered 3 tranny lines for my truck without looking at it and said they would replace them under warranty.

My question then is, do I just get my lines replaced or do I have any other issues like tranny problems or torque convertor issues?

Greg

Doesn't the fluid need to move through the system to be "pumped"? I understood that to be the deffinition of pumping.:rolleyes:

I missread the jello part. You are correct.

In talking about pumping you must consider internal vs. external flow. That's where the sump heater can get you into trouble at -40 and below. It gets the internal flow going to apply clutches and make heat while the external cooler and lines are blocked with jello.

In talking about pumping you must consider internal vs. external flow. That's where the sump heater can get you into trouble at -40 and below. It gets the internal flow going to apply clutches and make heat while the external cooler and lines are blocked with jello.

exactly. I think that if you simply dis-able the high idle feature, untill you can get it in to have it re-programmed, you will be just fine. After all, that is all the re-program does, halts the high idle untill its safe to run.

tell your mec that there is a download for the tranney in cold weather

I worked up in Fort St John BC and I was talking to the goodwrench svc tech,he said they have 60 dead Allisons ,like crafty said ,the oil gelled I guess thru the cooler ,no flow and BOOM,doesn't matter what failed ,my buddy Ken is very busy now 'till june I figure

25 straight trannies since feb 5. only three replacements. the rest rebuilt. 2 more weeks and i should be caught up. as much as I like the transmission I really want to work on something else. we had approx 60 to 65 down at work. could see more in the spring when people start towing trailers and fifth wheels.

LONG WINDED POST WARNING!

Dear Ann Landers.

I am in Indianapolis, Indiana and have had this same cold weather issue with my truck. I am living in a 5th wheel (heavy bad boy) traveling around the country contracting.

35000 miles on my duramax. Truck was parked facing into wind, weather got to –15 F. Let truck warm up 20-25 min. Got in to go to work, put in reverse and the truck rolled backwards (hill) into road. Like I had the transfer case in neutral. The trans selector light was blinking. I put it in park and light was steady. Put in D and it blinked. I had to get truck out of road, The engine revved to 2000-2300 as it crawled fwd. I also had a steady chk eng light. Shut off and hitched a ride to work.

Called a dealer and they said my spin on filter was plugged. Changed it. One week later, same scenario only this time I did not take foot off brake after putting in reverse. Blinking shift selector and steady check eng light. Shut off and got ride to work.

I talked with a couple of different dealers and none had heard of this cold weather issue. It will be at least another two weeks b4 I can take truck to dealer. I think I am going to get screwed on this. 1000 miles left on warranty and I pull a pretty heavy 5th wheel. I work 6 days a week and have put a total of 50 miles on my truck since the first incident happened a month ago.

1. Can anyone recommend a perf shop or tranny shop where I can at least get the trouble codes before I go to dealership?

2. Is there anyway to prove that this is what happened to my tranny or is there an easy way to see if I now have a blue converter?

3. Have I fried/ruined any clutches from the slippage that happened?

Thanks
Depressed Del

I am in Indianapolis, Indiana and have had this same cold weather issue with my truck. I am living in a 5th wheel (heavy bad boy) traveling around the country contracting.

1. Can anyone recommend a perf shop or tranny shop where I can at least get the trouble codes before I go to dealership? Thanks
Depressed Del

Many here recommend Branydon @ Fleece Performance for transmission upgrade work. Give him a PM or call.
Google Map shows him about 30 miles west of Indy.
http://www.fleeceperformance.com/

Thanks

Del,

Contact your dealer to get the trans repaired. I would be more than happy to fix your trans if damage has occurred but it would be on your dime and not warranty.. and this situation sounds just like the park warm up mode issue that others have experienced.

Crafty1 can probably send you in the right direction.

Brayden

To everyone w/ an 05 or older, the TC will start to fail in extreme temps.

At -55+ last week drove the truck from -20 temps area to area that was
-55+. Stopped long enough to fuel and throw some gear in the bed, then take back off.

Never shut the truck off, but had the high idle on. In that 35-40 min timeframe the tranny must have cooled dramatically. Once I started to pull off, threw an injector code and TC started slipping like there was no tomorrow. The truck never went into limp mode engine seemed to run fine, but truck would easily over rev. So babied it all the way home, 1500-1600 rpm.

Got back home and truck started pulling much better once in -20F temps.

At the dealership they replaced the 2 injectors and the tranny fluid was done, but they said the tranny and tc looked ok.

So to everyone, in extreme temps the cooler will "over cool" your tranny.

To everyone w/ an 05 or older, the TC will start to fail in extreme temps.

At -55+ last week drove the truck from -20 temps area to area that was
-55+. Stopped long enough to fuel and throw some gear in the bed, then take back off.

Never shut the truck off, but had the high idle on. In that 35-40 min timeframe the tranny must have cooled dramatically. Once I started to pull off, threw an injector code and TC started slipping like there was no tomorrow. The truck never went into limp mode engine seemed to run fine, but truck would easily over rev. So babied it all the way home, 1500-1600 rpm.

Got back home and truck started pulling much better once in -20F temps.

At the dealership they replaced the 2 injectors and the tranny fluid was done, but they said the tranny and tc looked ok.

So to everyone, in extreme temps the cooler will "over cool" your tranny.

So we can't drive our trucks in 50 below temps with the tranny failing? Did you have a winter front cover on?

To everyone w/ an 05 or older, the TC will start to fail in extreme temps.

At -55+ last week drove the truck from -20 temps area to area that was
-55+. Stopped long enough to fuel and throw some gear in the bed, then take back off.

Never shut the truck off, but had the high idle on. In that 35-40 min timeframe the tranny must have cooled dramatically. Once I started to pull off, threw an injector code and TC started slipping like there was no tomorrow. The truck never went into limp mode engine seemed to run fine, but truck would easily over rev. So babied it all the way home, 1500-1600 rpm.

Got back home and truck started pulling much better once in -20F temps.

At the dealership they replaced the 2 injectors and the tranny fluid was done, but they said the tranny and tc looked ok.

So to everyone, in extreme temps the cooler will "over cool" your tranny.

Not sure what is going on here unless the converter is somehow losing its charge and can't get the flow to refill. The ATF can gel in the trans aux cooler in extreme cold temps. The 2005's and earlier are better at resisting this than the 2006 and later though because of the shorter length of the aux cooler and the use of DEX3. TranSynd is recommended where use is below -40 degrees.

guys come on give the allison a break. There arent too many things that work well at -50* :rolleyes:

As crafty1 said, this is more a fault of the fact that ATF (and most oil) just doesnt flow down at that temp, not a "transmission problem" or "bad design"

fill 'er up with transynd and just run it..

Cold front was on and the truck never shut down for the duration of the trip! 15 hours.

Was on a rescue mission to pick up a stranded duramax owner who had an allison fail and a replacement 300 miles prior. (06 model) After his 2nd failure I decided to drive to rescue and throw his gear in the truck and turn around.

Apparently guys that live in those temps are putting a bypass valve on the cooler lines to block it off in those temps.

But an allison 6 speed failing after only 300 miles and the truck never shut down! Come-on!!! How rare is this!

My dealer told me that my fluid was completely toasted but the tranny and tc looked OK so I'll see when I pick it up today.

My surprise is that even with the truck running and never shutting down in those temps the tranny and high idle can't keep the fluid warm enough. There are plenty machines designed to operated in those temps, can't understand why a, electronic bypass valve wasn't added to the ($7500) powertrain package upgrade on a $50k truck??? This package has 100 other failsafes but no real extreme cold temp testing that verified this???

With the number of diesel trucks operating at these temps I'm suprised this hasn't been officially addressed.

So is it a bad idea to put a pad heater on an 05? Mine has problems with valves sticking in cold weather, like below 15 f causing range shift inhibited.

Putting the heater on the pan can help, help get you in trouble. Sure it means the pump gets pumping oil and making pressure to apply clutches. BUT it takes a LONG time before it gets any oil moving through the coolers, the air-to-oil in particular. If you start driving, the cold air may keep the fluid solid up there.
In this 2001 publication, Allison suggests a "sump heater" (with Transynd) be used for extreme temperature applications. Not sure what to think. http://www.allisontransmission.com/documents/product/13-TR-90,%20Rev%20E.pdf

So is it a bad idea to put a pad heater on an 05? Mine has problems with valves sticking in cold weather, like below 15 f causing range shift inhibited.
A Sump heater should not be needed in those temps. Maybe your truck needs a fluid change? The shift valves do get sluggish below -13F so they are not moved until it gets warmer than that. Depending on your fluid and its condition, you may have different performance.

The guys who typically run sump heaters are the ones where it gets to -25F or colder. The trouble with the heater is for the 2006 and later trucks where there is a warmup mode that makes heat with the torque converter. The sump heater was fooling the trans to think that it was warm enough to run this mode but actually the conventional Dexron6 can be gelled in the aux cooler. If this condition is combined with high idle being selected (makes heat faster), the converter can overheat in about 10 mins.

The service calibration put out by GM looks at other inputs to determine if it thinks it is cold enough that the cooler could be gelled in the cooler, but the bottom line is that you need to be running a good synthetic ATF like TranSynd or Mobil Delvac ATF in those temps to get it flowing.

Well my trans. was filler with new transynd. back in june of 08. The filters were just changed a few weeks ago. It is kind of tempermental as far as when it will say RSI. It will do it in reverse, Drive or sitting in park warming up. It is kind of a P.I.T.A. to have to turn the truck off, plug in the scan tool, read the code, clear the code, unplug scan tool, start truck and go about my day. It would be nice if I could just turn key and go.

A Sump heater should not be needed in those temps. Maybe your truck needs a fluid change? The shift valves do get sluggish below -13F so they are not moved until it gets warmer than that. Depending on your fluid and its condition, you may have different performance.

The guys who typically run sump heaters are the ones where it gets to -25F or colder. The trouble with the heater is for the 2006 and later trucks where there is a warmup mode that makes heat with the torque converter. The sump heater was fooling the trans to think that it was warm enough to run this mode but actually the conventional Dexron6 can be gelled in the aux cooler. If this condition is combined with high idle being selected (makes heat faster), the converter can overheat in about 10 mins.

The service calibration put out by GM looks at other inputs to determine if it thinks it is cold enough that the cooler could be gelled in the cooler, but the bottom line is that you need to be running a good synthetic ATF like TranSynd or Mobil Delvac ATF in those temps to get it flowing.

Is it always the same code/ valve hanging? If so whch one?

if its -50 I dont care what you do I wouldn't even consider getting my truck or anything diesel out for that matter. Thats insane

Didn't have diesels when I lived in Fairbanks; did have a bunch of gas GM P/u's and 2 Corvettes, 85 & 92. All trucks were auto, 85 Vette manual. Drove all vehicles year round, coldest for Vette's was a few 50 below days, usually garaged them when it was going to be colder than 30 below. Synthetic fluids in all, no problems. Did take a while to warm up, had to drive real slow for a while.

Did use frost plug heaters and a few silicone pad heaters (thin silicone pads with heating elements woven in it, 50 watts on up) silicone caulked to oil/trans pans. I might be inclined with the D/A, if I were still up north, to insulate the trans lines with foam pipe insulation, insulate the trans pan, and maybe put a few dc rated silicone pad heaters at strategic spots on the cooler that could be turned on and off inside the cab.

IIRC, they also had skirts that were mounted under the engine compartment that minimized air flow down out of the engine compartment. Kind of like a big flexible skid plate, just had to make sure it was well secured and didn’t hit anything real hot.

Also, a trick I used to warm the trans and transfer case and engine faster was to put the transfer case in neutral, after a short warm up period on the engine, and then place the trans in gear so it was working against a load. Warmed up the TC, trans and engine quiet nicely. Just had to be careful with all the other stuff that was still real cold. Oh yea, make sure park brake is on…

Also, a trick I used to warm the trans and transfer case and engine faster was to put the transfer case in neutral, after a short warm up period on the engine, and then place the trans in gear so it was working against a load. Warmed up the TC, trans and engine quiet nicely.

The allison already does this by itself. :cool: ;)



Basically when its below 32* it automatically puts the transmission in gear, but leaves the park pawl engaged (so the truck doesnt actually move forward). Then it puts the engine in high idle; so effectively its like you are sitting there powerbraking the trans/engine to 1100rpm or so. Loads up the trans and engine so they heat up fast.

The problem is the "cooler" works too well. Apparently the fluid turns to jello in the cooler, even with the truck running.

The 06's and newer have smaller diameter lines and larger cooler, so the effect is even more dramatic. Even the GM fix here in AK for some time was to bypass the cooler......until they started overheating in the summer.

With the cooler frozen the fluid gets too hot and smokes the TC, then the tranny.

Made it to the dealer after my trip, and the dealer inspected the tranny and tc, said it looked OK, but fluid was toast. Fix was to change fluid ($420) and "wait to see what happens." Hopefully it goes before the warranty is out.

Good luck in those temps guys, and try bypassing the cooler until spring. Run full syn fluid and go from there.

try just covering the cooler with cardboard ,so theres no airflow and turning off the high idle

Any Type Of Fluids In Those Conditions Will Not Perform Up To Their Standards (motor Oil,trans Oil,rear End Oil,shock Oil,power Steering Fluid,some Engine Coolants,washer Fluid,AND THE LIST GOES ON
Watch Tour Trans Temps ,never Get Much Over 150!

The allison already does this by itself. :cool: ;)



Basically when its below 32* it automatically puts the transmission in gear, but leaves the park pawl engaged (so the truck doesnt actually move forward). Then it puts the engine in high idle; so effectively its like you are sitting there powerbraking the trans/engine to 1100rpm or so. Loads up the trans and engine so they heat up fast.

Still, in my mind not the same as actually having the TC in neutral and trans in gear which does allow the TC to warm up also.

Still think there is something missing, here. In all my previous vehiciles with auto trans (I know, not an Allison) I never had these problems. Even before switching to syn trans fluid (Mobil 1). That's why I think if there was at least a trace of heat somewhere in the cooler/cooler lines then the jello blockages would not occur.

Sure do miss telling all those "50 below" stories. Sure do...:laugh_exp

Dam near gonna be that cold here in ILL. next 2 days. This oughta be real interesting on this site the next few days. The midwest Dmaxs havent been thru a whole lot of this extreme cold. Stay tuned......

Still, in my mind not the same as actually having the TC in neutral and trans in gear which does allow the TC to warm up also.

How is it not the same...????

If you sit there in drive at a stoplight, hold the brakes, and rev the engine up to 1200rpm how is that not going to heat up the trans or torque converter???

How is it not the same...????

If you sit there in drive at a stoplight, hold the brakes, and rev the engine up to 1200rpm how is that not going to heat up the trans or torque converter???

Exactly. The C3 and C4 clutches are applied while in Neutral (no path for power from input to output). This grounds the input shaft to hold the TC turbine, thus making heat. As far as I know, the Allison is the only trans to have this warmup feature. Other trans require the operator to put it in drive and power brake the trans to make heat.

The transmission and coolers are separated by at least six feet of line so it takes a long time to get any heat up to the front of the truck. Over 12 minutes with Dex6 at -30F/-35C, twice that long at -40. Using TranSynd cuts these times in half.

Exactly. The C3 and C4 clutches are applied while in Neutral (no path for power from input to output). This grounds the input shaft to hold the TC turbine, thus making heat. As far as I know, the Allison is the only trans to have this warmup feature. Other trans require the operator to put it in drive and power brake the trans to make heat.

The transmission and coolers are separated by at least six feet of line so it takes a long time to get any heat up to the front of the truck. Over 12 minutes with Dex6 at -30F/-35C, twice that long at -40. Using TranSynd cuts these times in half.

doh!! I was wrong. :o:

I thought it just put the trans in first, and then just used the park pawl to keep the output shaft from turning. THank you for correcting me crafty1. :)

doh!! I was wrong. :o:

I thought it just put the trans in first, and then just used the park pawl to keep the output shaft from turning. THank you for correcting me crafty1. :)
iS THAT THE FIRST TIME OR JUST THE FIRST TIME TO ADMIT IT:D

:funnypost :D Mike

Today I noticed a few red spots in the snow where my truck parks at work and sure enough it's tranny fluid. It's been pretty darn cold here this week so my truck will high idle while I let it warm up before leaving at the end of the day. Is the leaking a product of this Allison cold weather issue? I need to crawl under to see where it's coming from but I just noticed it today so I haven't had a chance.

Today I noticed a few red spots in the snow where my truck parks at work and sure enough it's tranny fluid. It's been pretty darn cold here this week so my truck will high idle while I let it warm up before leaving at the end of the day. Is the leaking a product of this Allison cold weather issue? I need to crawl under to see where it's coming from but I just noticed it today so I haven't had a chance.
wELCOME TO THE CLUB:(

Well I fired it up after work today and ran back in to let it warm up. Came back out and saw fresh drippings but now I knew where it was coming from. There is a line just in front of the suspension on the right side that hangs down and goes up to what I'm guessing is either the return or supply line for the tranny cooler. At least it's not coming from transmission.

I haven't crawled underneath to find out if it's a hole in the hose or a bad fitting......too damn cold out! I'd be nice if it was a fitting I could just tighten up but I'm not sure what type of connections are underneath there.

Called the dealer and have an appointment set up for Monday. I hope it'll hold up for a while because I need to use it this weekend.

Oops. My original post said "transfer case" . That's what I was warming up besides the trans. Also, as things warmed up, the trans would actually shift gears even at idle as things warmed up. Granted, that was in the carb world with auto chokes. Even the computer run fuel injected ones would still run at higher than normal temp idle rpm's and shift up at least one gear, IIRC. I know these trucks/computers are much more sophisticated, but just curious if doing what I've posted would help, which is: trans in gear, transfer case neutral, trans lines inuslated along with trans sump, air flow restricted to cooler, external heat applied to cooler while truck at idle, and syn trans fluid.

Again, I understand vehicles have changed (to the better) from my time in AK, but that is kind of the point. And, yes I understand that the Allison is programed to do certain things that the old time autos didn't do. So, maybe the stuff I've suggested wouldn't work. But, maybe it would?

I see there is a thread on a leaking hose epidemic that has been ongoing since about 2006 that seems to rear it's ugly head when it gets cold outside. There is a TSB on this and it appears to be my problem.

Minn-kota,

1st... If you have not had the tsb done DO NOT use the high idle at those temps. This is for 06s and up.

Once the tsb has been performed the truck will high idle for 1 minute, then normal idle for one. This cycle will continue, so not to overheat the torque convertor. W/O the tsb it can and will overheat the tc before you know it at those temps.

Also, I know everyone is saying to run transynd, but why doesn't GM have this our expensive transmission to begin with? $6000 warranty job or extra $50 (gm cost) from the start. Sounds like someone has been trimming fat to keep the bottom line where they want it.

Just frustrating, to own a vehicle that is highly used in these arctic regions and the manufacture doesn't equip it to do this from the factory.

Oops. My original post said "transfer case" . That's what I was warming up besides the trans. Also, as things warmed up, the trans would actually shift gears even at idle as things warmed up. Granted, that was in the carb world with auto chokes. Even the computer run fuel injected ones would still run at higher than normal temp idle rpm's and shift up at least one gear, IIRC. I know these trucks/computers are much more sophisticated, but just curious if doing what I've posted would help, which is: trans in gear, transfer case neutral, trans lines inuslated along with trans sump, air flow restricted to cooler, external heat applied to cooler while truck at idle, and syn trans fluid.

Again, I understand vehicles have changed (to the better) from my time in AK, but that is kind of the point. And, yes I understand that the Allison is programed to do certain things that the old time autos didn't do. So, maybe the stuff I've suggested wouldn't work. But, maybe it would?

this is a bad idea in my own opinion. Seeing as you have no way to stop the output shaft from spinning (because the xfer case is in neutral, you cant press the brakes to stop the trans), Id love to hear the interesting noises when you go to shift it into park, especially if you revved it up and let the trans shift up into the higher gears. :eek:

please guys....just use the regular high idle. It works 10x better than any other method...and it wont destroy the park pawl. :)

Minn-kota,

1st... If you have not had the tsb done DO NOT use the high idle at those temps. This is for 06s and up.

Once the tsb has been performed the truck will high idle for 1 minute, then normal idle for one. This cycle will continue, so not to overheat the torque convertor. W/O the tsb it can and will overheat the tc before you know it at those temps.

Also, I know everyone is saying to run transynd, but why doesn't GM have this our expensive transmission to begin with? $6000 warranty job or extra $50 (gm cost) from the start. Sounds like someone has been trimming fat to keep the bottom line where they want it.

Just frustrating, to own a vehicle that is highly used in these arctic regions and the manufacture doesn't equip it to do this from the factory.

The problem is that to factory install, you have to pay the overcost for ALL the trans you build when only a small percentage needs it. That adds up to 8 to 10 Million dollars a year!

The calibration was changed when it was discovered that Dexron6 wasn't flowing in these temps so the trans will not overheat.

Still not the best to not have cooling and lube flow at these temps. But like anything else it takes to work in those temps; syn pwr steering fluid, arctic engine oils, extra heaters, heavy antifreeze mix... the owners and dealers in those areas should prep them accordingly.

Good to know... what fails inside?

The converter. No flow through the converter = burnt up converter.

Guess I should have finished my old war story. After warmed up, shut down engine, once it has stopped, place transfer case in gear and trans in park/neutral. Start truck up again, then place trans in gear and drive off. As stated, not allison, but worked with what I had way back then (basically 1977 - 81; 86 - 99).

thanks!!! its my toy and i wouldnt sell it for anything. i havent drivin it since august:(

Why haven't you dorve it?

Crafty, I understand the issue with the additional associated costs, but the premium paid for the DMax/Allison upgrade should demand superior fluids!!! Look at the price for a new Merc/bmw diesel over a DMax, and they have dramatically more complex/expensive parts!

Second this should never happen to a vehicle that is never shut off. I drove from -20 temps (truck runs fine, and in garage), then to -50, stop for 45min then drive off again. Ba'am, TC starts slipping like hell.

This what suprised the hell outta me, with all of the safeguards and electronics that this package has and it has this problem. How hard would it be to have an internal bypass valve to bypass the external cooler loop? Or just ensure that all owners can purchase transynd at cost from their dealer if running in those temps, and make it known to all dealers and customers.

Instead we will let people potentially break down in -50 temps and risk injury or serious harm.

If you've never been to Tok, AK take a trip there and see how long it takes you to get to a place that has an actual repair shop, or hotel.:D

My $.02