Pulled my nearly 10,000 lb bumper pull toyhauler through the mountains over the weekend and was impressed with the truck. Found out I prefer using manual shifting over auto when Tow Haul Mode is engaged. Auto mode simply allows to much shifting when in the constant up and down terrain and on steep down hill terrain the tranny can be forced into what I believe is to low a gear causing the RPMs to go way to high for my comfort level. I thought I saw well over 4000 RPM a couple of times when braking prior to a downhill turn. Manual mode lets me control the gear and when I need to slow a little more the truck and trailer brakes are more than enough to control my speed. Just what is the redline on the Duramax anyhow? I can’t find any marks on the tach so apparently GM doesn’t want me to know.
Overall I was very pleased with pulling a heavy load through the mountains. I think my 7.3 PSD had a little more power but it had a Edge Evolution Tuner installed so that’s not a real comparison. My Duramax is rated a lot higher in horsepower than my PSD was even with the tuner installed but it just doesn’t seem like it. I love the Allison though. I never had a Tow Haul mode in my Ford and always hated pulling down steep hills because when you hit the brakes the torque converter would unlock and make it harder to control speed. Tow Haul Mode and 6 speeds is going to spoil me.

When I asked about this at the dealer they said as long as you don't hit the redline under acceleration it was fine. Tow/Haul mode towing my 11k lb trailer does the same thing when going down hill at speed and braking to slow it down and control speed it downshifts to the point the RPMs are 3500-4k. I switch out of T/H mode and then hit the throttle to shift up and then brake again.

Manual tow haul mode seems to work fine for me as well. Next best thing to a manual tranny in my opinion

I think if you do some searching on here you will find that it is normal. If I remember right, under acceleration, stock engine was limited to around 3200. Some have even said that GM removed the redline because of complaints it went over redline during downshifting on the old body style. True or not, unsure. But it makes sense. It did on my old ones. I don't think you are hurting your engine at all though. The truck wouldn't do it if it wasn't intended to. The D Max/Ally has done that since the beginning.

Yep, computer won't allow over rev.

Just came down a 6% long grade yesterday. 05 LLY. Montana side of Lost Trail Pass. Towing about 10,000. The Allison worked perfect and Rpms were less than 3200. Very little braking required. Speeds 25-30.

One thing I noticed was the fuel mileage on the DIC. When I was in tow haul and the Allison grade braking the DIC indicated 0.0 MPG. It did this all the time the Allison was in control. I expected it to read 70-99 mpg as there should have been very little fuel flow.

The only issue I see with the " manual control" is that the "grade braking" doesn't work with it.
The Allison Manual say " Grade Braking is not available when Range Selection Mode is active".
I personally LOVE this feature!!!

The only issue I see with the " manual control" is that the "grade braking" doesn't work with it.
The Allison Manual say " Grade Braking is not available when Range Selection Mode is active".
I personally LOVE this feature!!!


When in manual mode - you are doing manual grade braking........

So grade breaking still does work - just not automatically.......

I had it in T/H to grade brake going down long steep grade the other day - full of people is all - not towing. At one point towards the bottom it's going a bit fast so I tap on the brake peddle - it rev'd up to 3,500 way more than needed. Clicked off T/H when that happened!

:cool:

hmmm...I think I read in my manual that you can over rev while down shifting on a grade. The computer only protects you under acceleration. RTFM guys.

Nate

I wish GM was a little more clear on the red line issue. I noticed when it was in auto Tow Haul mode and going up hill I got down shifts that revved up to 3200 and would go higher if I didn't back out a little. I took that 3200 as a 'rule of thumb' when manual shifting on uphills. Actually I'd let the tranny downshift itself, note the RPM, then I'd click down one on the shift paddle to make it hold that gear until I was ready to upshift.
I'm wondering how my truck is going to do in 4 years when I have to do an emissions test here in Arizona (Maricopa County). Their diesel emissions test requires you to literally floor it while in park and they then test the rev limiter and soot emissions. Have to repeat that test about 3 times for 15 seconds or so. I hated it! If the RPM level on the LMM is not 'fixed', that test will be a nightmare!

Guys...lol...read the manual and search on here if needed.
Ok, the truck will give the engine FUEL up to 3250 rom (although I've logged EFI at 3450 one time). It will cut the fuel at the point. That is the FUELED "redline".
I have seen my truck over 4500 rpm in the tow haul Manual mode and it upshifted itself.
It will not let it hurt itself, even in the M mode it will upshift if needed.

The truck is DESIGNED to do this, in fact it was a selling point...

They do not include a redline anymore because people wouldn't read the manual and realize that when in tow haul mode, the grade braking would switch on and it would fly into the red line and people would freak...

It's OK to let it do it's job, it's made for this. :)

Now when the grade brake is on, and you come to the bottom of the hill and you want the truck to go back into 'regular' driving instead of slowing the load...just touch the accelerator pedal and it'll put itself in the correct gear and go on rolling...
If you're in M mode just hit upshift and go on your way...

I wish GM was a little more clear on the red line issue. I noticed when it was in auto Tow Haul mode and going up hill I got down shifts that revved up to 3200 and would go higher if I didn't back out a little. I took that 3200 as a 'rule of thumb' when manual shifting on uphills. Actually I'd let the tranny downshift itself, note the RPM, then I'd click down one on the shift paddle to make it hold that gear until I was ready to upshift.
I'm wondering how my truck is going to do in 4 years when I have to do an emissions test here in Arizona (Maricopa County). Their diesel emissions test requires you to literally floor it while in park and they then test the rev limiter and soot emissions. Have to repeat that test about 3 times for 15 seconds or so. I hated it! If the RPM level on the LMM is not 'fixed', that test will be a nightmare!

We do those tests here in California on the heavy trucks. Unless they change the procedure, these trucks will pass no problem. The only ones that will have issues are the ones with the programmers installed that produce heavy smoke, but they will be fine if they are deactivated. We have one of those machines. Called an opacity meter, it only measures the amount of light that is blocked by the exhaust smoke. It doesn't even know the RPM. I guess they could change it to make it harder to fool, but now it would be easy to trick.

Guys...lol...read the manual and search on here if needed.
Ok, the truck will give the engine FUEL up to 3250 rom (although I've logged EFI at 3450 one time). It will cut the fuel at the point. That is the FUELED "redline".
I have seen my truck over 4500 rpm in the tow haul Manual mode and it upshifted itself.
It will not let it hurt itself, even in the M mode it will upshift if needed.

The truck is DESIGNED to do this, in fact it was a selling point...

They do not include a redline anymore because people wouldn't read the manual and realize that when in tow haul mode, the grade braking would switch on and it would fly into the red line and people would freak...

It's OK to let it do it's job, it's made for this. :)

Now when the grade brake is on, and you come to the bottom of the hill and you want the truck to go back into 'regular' driving instead of slowing the load...just touch the accelerator pedal and it'll put itself in the correct gear and go on rolling...
If you're in M mode just hit upshift and go on your way...

EXACTLY.

These trucks are specifically designed to do all the things you guys are mentioning, and it WILL NOT HURT ITSELF. I just put it drive and tow/ haul and let it do it's thing.

I figured the truck was designed to not let it hurt itself, I simply don't feel comfortable letting the engine rev so high on engine braking. It's not a crime to use the truck and trailer brakes to slow down. Besides those high revs make it harder to hear my music on the radio.
Jason, your comment,
"It will not let it hurt itself, even in the M mode it will upshift if needed."
, are you saying that if I'm in Manual Tow Haul Mode with 3rd selected and the RPM exceeds a certain value it will shift up to 4th automatically? I didn't think it could do that and that's why I wanted to know a specific red line number so that I would'nt exceed it while driving in Manual.

Hi Max!

Yes, that's exactly what I'm saying... If you're in any gear selected by manual mode and it goes over a certain RPM (I BELIEVE it's 5k because that's the max of the allison input) it WILLLLL upshift itself into the next higher gear.

If you're uncomfortable with it, by ALL means there's NOTHING wrong with using your service and trailer brakes to slow the vehicle though. I do know that it does get noisy w/ all that RPM.

Pulled my nearly 10,000 lb bumper pull toyhauler through the mountains over the weekend and was impressed with the truck. Found out I prefer using manual shifting over auto when Tow Haul Mode is engaged. Auto mode simply allows to much shifting when in the constant up and down terrain and on steep down hill terrain the tranny can be forced into what I believe is to low a gear causing the RPMs to go way to high for my comfort level. I thought I saw well over 4000 RPM a couple of times when braking prior to a downhill turn. Manual mode lets me control the gear and when I need to slow a little more the truck and trailer brakes are more than enough to control my speed. Just what is the redline on the Duramax anyhow? I can’t find any marks on the tach so apparently GM doesn’t want me to know.
Overall I was very pleased with pulling a heavy load through the mountains. I think my 7.3 PSD had a little more power but it had a Edge Evolution Tuner installed so that’s not a real comparison. My Duramax is rated a lot higher in horsepower than my PSD was even with the tuner installed but it just doesn’t seem like it. I love the Allison though. I never had a Tow Haul mode in my Ford and always hated pulling down steep hills because when you hit the brakes the torque converter would unlock and make it harder to control speed. Tow Haul Mode and 6 speeds is going to spoil me.


I do the same thing as you do. Maybe the RPM's don't hurt it but I just don't like it. I can tell you one thing though that I pulled a nasty hill which got my fan on then coming down the other side I smoked the crap out of my brakes when maybe I should have let the Allison do it's thing. I layed off the T/H because the trans was hotter then the engine. I guess sometimes you just can't win.

Cool breeze--------- Your trans will run cooler in TH mode.

I use the TH mode on my big fiver. It works like a dream. I don't know why anyone would rather use ther service brakes over an engine brake. It is there for a reason, and is safer. You are never going to be as smart as the trucks computers. The fueled redline is about 3200 rpm. the decel redline is 4800 rpm. If you would read your manual, you would learn all kinds of neat thing about your trucks. The truck will not let you hurt it, you can grab the shifter and manually drop it into 1 st gear at 100 mph and not hurt it. My favorite allison feature is the cruise grade braking, all I gotta do is steer the truck. In that mode the engine and tranny do everything they can to maintain your preset speed. My truck and trailer weigh 26,000 and the cruise grade braking can hold it all back coming down a windie 5% grade with no service brakes at all.

With my first D/A ,(03' LB7), I was in tow/haul mode going down a fairly steep secondary mountain road while towing a 34' 5er, I started picking up speed and tapped the brakes, the rpm went up to 3200-3400 and that was when they DID show a redline, not proud to admit this, but I also hadn't read my manual on how the Allison worked, when the rpm shot up, I freaked out, put the truck in neutral to keep from red lining:eek:, and used the trailer brake to help slow me down. When I got to the campground, with brakes a little hot, I broke down and read my manual. WHEWWW!, learned about a whole other world of towing with the Allison. It's a lot smarter than I am and when in tow/haul mode going down a steep grade
depending on when you "kick it in", it's dumping fuel, my "ave mpg"
showing on the DIC also goes up, I'm not using any fuel, the Allison is now in control. I will use my "M" manual setting sometimes if I'm going up and down numberous steep mountains in a row...or not..it'll kick down on it's own. Again, as stated earlier, "IF" you do use "M" going down hill you've by-passed the Allisons braking interventon in the process. Going
down any mountain, I have it in tow/haul and let the Allison use it's computer brain, to this point, it has worked perfectly. As stated earlier, read your owners manual, it has a wealth of information in it. Also as stated earlier, leaving the truck in tow/haul while towing does tend to help keep egr and tranny temps. down better than you can in manual.

Also as stated earlier, leaving the truck in tow/haul while towing does tend to help keep egr and tranny temps. down better than you can in manual.[/quote]

Let me clarify, the entire trip was made with the truck in tow/haul mode. We're talking about the differences between auto and manual while still using tow/haul mode. If I'm using manual and select a gear higher than Allison would have selected in auto, I'll bet my egr and tranny temps are lower at the bottom of the hill. The brakes will be a little warmer though but that doesn't mean overheated.

I love the Tow/Haul mode...won't leave home without it! The D/A does a great job and is much smater than I!

Well what keeps or helps keep the heat down is the Torque converter locks up into second gear and stays locked through all the other gears keeping heat down.
When the torque converter is unlocked (in the lower gears) it's like slipping the clutch a bit in a manual trans when pulling away from a stop light to get a smooth transition from a stop. The by product of that friction is heat; the torque converter operates very similar...With all the friction of the TQ unlocked, it creates the heat.
Tow Haul puts the tranny in a different shift mode (higher RPMs before shifting) and lock the TQ converter after it shifts into second...
You can feel it lock up, it feels like it 'shifts' around 21 - 28 mph depending on your throttle position.

Note to self: go home re-read manual! Stop kicking it out of tow haul when rpms reach around 3500 - 4000. I knew better but it just sounded to wound up. Will have to try to get over that! Really loud when fan clutch kicked in.

LOL - Yeah the fan... what I lovingly call the 'turbo prop' :D
I shouldn't make fun of it to much, it sure does a good job! It just sounds like it's about to take off...

First ! I would not kick it in & out of towhaul while driving and towing, that is hard on the transmission, and not wise.
Put it in towhaul and leave it in,if you want to take it out,then come to a stop.
Same as when putting it in towhaul, at a stop.

Second ! The more you take the engine rpm`s to the redline, you are risking eventually causing damage.


3rd ! Even if you manual shift and want to up shift to 6th gear, it won`t go into 6th until you`ve reach the proper rpm`s and speed, especially in towhaul.

4th ! I have asked every GM diesel tech in my large city on Dmax`s rpm`s max and reline and their responce is, I don`t really know. (morons)
The Cummins in-line 6 has a lower rpm re-line, than the P.S. and Dmax V8`s

Me personally, never over 3200 rpm, mostly around 2800-3000 pulling steep grades.

First ! I would not kick it in & out of towhaul while driving and towing, that is hard on the transmission, and not wise.
Put it in towhaul and leave it in,if you want to take it out,then come to a stop.
Same as when putting it in towhaul, at a stop.

Second ! The more you take the engine rpm`s to the redline, you are risking eventually causing damage.


3rd ! Even if you manual shift and want to up shift to 6th gear, it won`t go into 6th until you`ve reach the proper rpm`s and speed, especially in towhaul.

4th ! I have asked every GM diesel tech in my large city on Dmax`s rpm`s max and reline and their responce is, I don`t really know. (morons)
The Cummins in-line 6 has a lower rpm re-line, than the P.S. and Dmax V8`s

Me personally, never over 3200 rpm, mostly around 2800-3000 pulling steep grades.

OK, i'm not going to turn this into a pissing match but there are some points here I'll comment on...

1st! The tow haul mode is a electronic switch the commands a different SHIFT pattern and for the TQ converter to lock and unlock at different rates...that is all - it doesnt raise line pressure or do any other magnificent thing...
You DO NOT have to come to a stop to put it in or take it out of tow/haul...all you're doing when you turn it off and on is commanding a different shit mode and TQ converter lockup parameters. I've SEEN the TCM programming, it's black and white ;)

2nd! The engine is DESIGNED to do this.... You're not creating extra torque or 'loading' the engine with fuel and commanding it to make power... You're going against compression and back pressure. I have a EFILive tune where I command MORE turbo pressure with NO throttle position (it's essentially a turbo brake - that works GREAT). Is there extra stress on putting the engine in that range? Sure... There's extra stress on the motor when you go from 1500 RPM to 2000 RPM, but it's MADE to do it... no issue IMO.

3rd! Bingo! the manual mode LOCKS out a UPPER range... If you select to lock it in 4th gear, it will shift normally up to 4th gear and attempt to keep it in 4th gear.
If you over spin it (4800 RPM i just saw up there) it WILL upshift itself into 5th even though it's 'locked' into 4th.... it's a failsafe, it will protect itself that way.

4th! I don't know if you've read the entire post, but i think I see where the mis-understanding is... are you thinking we're talking about climbing a hill or descending it with your foot off the fuel pedal.

Wow, I can't believe I actually started a post that got into it's 3rd page. That's never happened before on any forum for me.
Seriously, I've gotten a lot of information out of this so far so I want to say thanks and keep it coming, maybe I can get a 4th page too.
I've read a lot of comments about "read the manual" and I actually did read the manual almost word for word. Sections about tow/haul and engine/transmission stuff I probably read 2 or 3 times to make sure that I got it all. However, that was a few months ago and prior to any road trips or heavy towing like I've done lately. I do think when I get time I'm going to get the manual out again and re-read all the towing sections. Now that I've used it and experienced it I'll probably get more out of it than the first time. Maybe it'll actually have redline limits in there somewhere in the small print this time.

This is for those of you who do not quite understand a diesel engine. You can hold your foot to the floor and have your engine "sitting" on the govenor all day long. It will not hurt it, they are designed to work within these parameters. I am a heavy diesel mechanic and we run our engines at peak rpm's all the time. As long as it does not get hot you are not hurting it. Also, on our trucks, they are designed so you can not hurt it. The govenor keeps you from overspeeding the engine. It controls the fuel delivery, too much rpm's mean you will get less fuel so you do not exceed preset rpm limits. The trans has built in safegaurds also. Too many rpm's will get you an upshift, wheather you want one or not. It is pretty easy to understand; you are not going to hurt your engine or trans if you let it do its job.

This is for those of you who do not quite understand a diesel engine. You can hold your foot to the floor and have your engine "sitting" on the govenor all day long. It will not hurt it, they are designed to work within these parameters. I am a heavy diesel mechanic and we run our engines at peak rpm's all the time. As long as it does not get hot you are not hurting it. Also, on our trucks, they are designed so you can not hurt it. The govenor keeps you from overspeeding the engine. It controls the fuel delivery, too much rpm's mean you will get less fuel so you do not exceed preset rpm limits. The trans has built in safegaurds also. Too many rpm's will get you an upshift, wheather you want one or not. It is pretty easy to understand; you are not going to hurt your engine or trans if you let it do its job.


Let's add in "as long as it's stock".

lol That's a good addition ;)

Unless you raise the govenor rpm's, I stand by above.

Even with the wick turned up you can get away with it?

I wouldn't trust it, I think when you do anything to add HP you need gauges and you need to monitor them. All that stuff changes so many parameters that you'll have no idea whats going on until it might be to late.

Jasondt2001, good follow up. Where in the world does some of this info come from, "you should come to a stop before you put it in, or take it out of Tow/Haul??:eek:. You don't even have to do that when putting the truck in 4 wheel high. Some in here REALLY need to read their owners manual on how the Allison works, it'll really help you to understand it better:D

Cool breeze--------- Your trans will run cooler in TH mode.

I use the TH mode on my big fiver. It works like a dream. I don't know why anyone would rather use ther service brakes over an engine brake. It is there for a reason, and is safer. You are never going to be as smart as the trucks computers. The fueled redline is about 3200 rpm. the decel redline is 4800 rpm. If you would read your manual, you would learn all kinds of neat thing about your trucks. The truck will not let you hurt it, you can grab the shifter and manually drop it into 1 st gear at 100 mph and not hurt it. My favorite allison feature is the cruise grade braking, all I gotta do is steer the truck. In that mode the engine and tranny do everything they can to maintain your preset speed. My truck and trailer weigh 26,000 and the cruise grade braking can hold it all back coming down a windie 5% grade with no service brakes at all.


I know I heated the hell out of the trans going up the hill in T\H. Just was a baby I guess and didn't want to see the trans take all that pressure on the way down the hill. Temp on trans was skying yet the engine was at 205. Live and learn.

OK, i'm not going to turn this into a pissing match but there are some points here I'll comment on...



I left out all your explaintions because they board me.
All I can say is you will have to
"LIVE & LEARN BY YOUR MISTAKES"

I know I heated the hell out of the trans going up the hill in T\H. Just was a baby I guess and didn't want to see the trans take all that pressure on the way down the hill. Temp on trans was skying yet the engine was at 205. Live and learn.

Check your fluid levels, this tranny is SUPER sensitive to being over filled and heating up. :)

I left out all your explaintions because they board me.
All I can say is you will have to
"LIVE & LEARN BY YOUR MISTAKES"
Oh, wow... I'm so sorry I board you Mr. Wizard... :rolleyes:
BTW - It's BORED.;)

When I make mistakes, I'll learn from 'em, and I'll be sure to post them here so you can point fingers and laugh, ok? Until then, good-day :D

Oh, wow... I'm so sorry I board you Mr. Wizard... :rolleyes:
BTW - It's BORED.;)

When I make mistakes, I'll learn from 'em, and I'll be sure to post them here so you can point fingers and laugh, ok? Until then, good-day :D

WOW ! I just noticed you don`t even have a LMM either.
Trust me if you drive the way you explained to me on how to drive there won`t be any finger pointing from you except in a mirror.

I'll take notes ;)

I've seen both the LMM and LBZ transmission tunes, (I've even seen a few LLY ones) and they're the same.

Like I said, i'm not trying to turn this into a pissing match, if you read the manual or even the Allison Supplemental Manual you could enjoy your truck a bit more. I'll include the link....
Here's the brochure... http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA5521EN.pdf
Here's some FAQ: http://www.allisontransmission.com/service/faq/index.jsp?CategoryID=11#239

Here's a couple things asked here....

Q. Tow/Haul vs. Normal Mode - What's the difference between Tow Haul and Normal Mode?
A. Tow/Haul (T/H) shift mode significantly changes the transmission's shift pattern to reduce shift cycling and to deliver better performance, control, and cooling when towing/hauling heavy loads. For instance:

* Upshift points are raised at light to mid throttle position to use more of the engine's available power for accelerating.
* Downshift points are raised to enhance engine braking to help slow the vehicle.During deceleration, the torque converter clutch (TCC) remains applied at closed throttle to much lower vehicle speeds to significantly improve the effect of engine braking.
* During acceleration, the TCC is applied in 2nd range and remains applied in 3rd, 4th, and 5th. This improves the drivetrain efficiency and significantly lowers transmission sump temperature when towing heavy loads. In Normal mode, TCC generally applies only in higher ranges and is dependent on throttle position.

Q. Engine Speed - What is an acceptable engine speed after a preselect or grade braking downshift?
A. The TCM is programmed to command downshifts only when the resulting increase in engine speed will not exceed factory-set limits. Specifically:

For the LB7 and LLY diesel engines: Maximum engine speed immediately following a preselect or grade braking downshift can be as high as 4,000 RPM. After a grade braking downshift, if vehicle speed continues to increase, an upshift will occur at 4,800 RPM engine speed.

For the L18 gas engine: Maximum engine speed immediately following a preselect or grade braking downshift can be as high as 4,650 RPM. After a grade braking downshift, if vehicle speed continues to increase, an upshift will occur at 5,000 RPM engine speed.


Q. Engine Speed - If I have manually preselected a lower range resulting in a downshift, but the vehicle is allowed to continue to accelerate, will the transmission upshift?
A. If the transmission has been manually preselected by the driver to prevent an upshift, the transmission will NOT upshift if the vehicle speed is allowed to increase beyond the normal operating range of the engine.

Q. Automatic Grade Braking - When will I get a downshift?
A. There is no 'fixed' shift point for a 'grade braking downshift', however, the shift will never occur such that the engine speed following the shift exceeds GM Truck guidelines. Also, the shift will never occur without depressing the brake pedal.


Hope this clears somethings up.

I'll take notes ;)

I've seen both the LMM and LBZ transmission tunes, (I've even seen a few LLY ones) and they're the same.

Like I said, i'm not trying to turn this into a pissing match, if you read the manual or even the Allison Supplemental Manual you could enjoy your truck a bit more. I'll include the link....
Here's the brochure... http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA5521EN.pdf
Here's some FAQ: http://www.allisontransmission.com/service/faq/index.jsp?CategoryID=11#239

Here's a couple things asked here....


Hope this clears somethings up.


Ok, thank you.

This is kind of like when a over educated person with no on the job training whats so ever, and never worked a job in his life.
Hired to be a general manager and all the blue collars has to show him how the job is done, and do it for him.
Over educated on paper, useless in real life situations.

I know you can't be talking about me....
Over educated?!??! ROFLMAO... I have SOME college, but I got me GED - Good Enough Diploma in HS because I kept screwing around.

I'm pretty damn useful in real life situations actually, not quite McGyver but I'm pretty handy indeed.

I'm sorry you're so closed minded, I wasn't doing all this to make you feel like an asshole, you're doing a GREAT job at that yourself. I was just trying to help educate you on how great of a vehicle you happen to have.
G'day Sir. :D

This comment from that FAQ section/post disputes that the truck will upshift above the manually selected gear when the the RPM exceeds 4800. I think talked about back on page 2.

Q. Engine Speed - If I have manually preselected a lower range resulting in a downshift, but the vehicle is allowed to continue to accelerate, will the transmission upshift?
A. If the transmission has been manually preselected by the driver to prevent an upshift, the transmission will NOT upshift if the vehicle speed is allowed to increase beyond the normal operating range of the engine.

The key here is the 'normal operating range of the engine'.
Exceeding 4800 + rpm is going out of normal operating range and will up shift.

I'll take notes ;)

I've seen both the LMM and LBZ transmission tunes, (I've even seen a few LLY ones) and they're the same.

Like I said, i'm not trying to turn this into a pissing match, if you read the manual or even the Allison Supplemental Manual you could enjoy your truck a bit more. I'll include the link....
Here's the brochure... http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA5521EN.pdf
Here's some FAQ: http://www.allisontransmission.com/service/faq/index.jsp?CategoryID=11#239

Here's a couple things asked here....


Hope this clears somethings up.



THANKS FOR THE LINKS! There is MUCH more info in that Allision brochure than our owners manuals. And layed out in an easy to read fashion. A keeper!

;)

THANKS FOR THE LINKS! There is MUCH more info in that Allision brochure than our owners manuals. And layed out in an easy to read fashion. A keeper!

;)

Glad I could help Jimmy!! :thumb:

I left out all your explaintions because they board me.
All I can say is you will have to
"LIVE & LEARN BY YOUR MISTAKES"

WOW! That was "RUDE" When someone gives info,you should take it with a thank you! If you already know all thats has been explained,you still say thank you.

Jason.Keep up the good work:ro)

That FAQ is pretty good but I'm wondering how old it is. It never mentioned LMM series, only pre-LMM.

I dont know why GM even puts manual mode in. All it does is breed uninformed people who think they know how to shift better than the ECM and TCM that GM put so much R&D into programming and perfecting to operate in the most efficient and SAFEST way possible. :)

put it in drive, tow/haul on, and leave the freaking thing alone. This is what the allison transmission was bred for. NO you arent going to hurt the damn thing at 4000+ rpm, I dont care if "it doesnt feel right" or "well I drive a semi and they redline at like 1000rpm, so why should my duramax be any different, theyre both diesel engines arent they?". If they can program a computer to turn your headlights on when it gets dark, dont you think they can program a computer to prevent excessive speed or something else from damaging a 10,000 dollar engine????????????? If you are in a huge downhill and the trailer keeps pushing you faster and faster and the engine rpm rises above 4800 or so, it will UPSHIFT to drop the engine rpm.

If you want to play with gears/shifting that badly, buy a manual trans. :)

ben

I dont know why GM even puts manual mode in. All it does is breed uninformed people who think they know how to shift better than the ECM and TCM that GM put so much R&D into programming and perfecting to operate in the most efficient and SAFEST way possible. :)

put it in drive, tow/haul on, and leave the freaking thing alone. This is what the allison transmission was bred for. NO you arent going to hurt the damn thing at 4000+ rpm, I dont care if "it doesnt feel right" or "well I drive a semi and they redline at like 1000rpm, so why should my duramax be any different, theyre both diesel engines arent they?". If they can program a computer to turn your headlights on when it gets dark, dont you think they can program a computer to prevent excessive speed or something else from damaging a 10,000 dollar engine????????????? If you are in a huge downhill and the trailer keeps pushing you faster and faster and the engine rpm rises above 4800 or so, it will UPSHIFT to drop the engine rpm.

If you want to play with gears/shifting that badly, buy a manual trans. :)

ben

My tranny is a long winded SOB.It loves 6th gear towing my towhauler,egt's were 1400*+ even starting up a hill,it didnt want to down shift,had to use the manual mode to lock in 4th.

WOW! That was "RUDE" When someone gives info,you should take it with a thank you! If you already know all thats has been explained,you still say thank you.

Jason.Keep up the good work:ro)

Well then , Thank you.
The part you`all is missing what is on paper/print is not always the same as when your in real life situations and only has been done in perfect conditions.
I very well could be wrong but I feel with over 40 + years driving diesels and have been in just about every driving situation possible.
Testing and dealing with actual dynos for over the past 15 years, I have found the specs shown by all manufactures including GM, in most cases are not even close to what they advertise.
So I`m pretty comfortable with what I do and believe in, because I have been in real life situations, not on paper/printed one`s.

I dont know why GM even puts manual mode in. All it does is breed uninformed people who think they know how to shift better than the ECM and TCM that GM put so much R&D into programming and perfecting to operate in the most efficient and SAFEST way possible. :)

If you did not have the manual shift it would skip a gear when downshifting in most cases.
Sixth gear is actually overdrive if you didnot have the manual shift it would skip 5th and go into 4th gear,unless you can work the throttle just right.

put it in drive, tow/haul on, and leave the freaking thing alone. This is what the allison transmission was bred for. NO you arent going to hurt the damn thing at 4000+ rpm,
I presume you know this with real life experances ???
I dont care if "it doesnt feel right"
I guess until you toast a engine,or trash a trans ( I have) trusting all this so called computer controlled crap then you will continue believing what is on paper.
or "well I drive a semi and they redline at like 1000rpm, so why should my duramax be any different, theyre both diesel engines arent they?".

Yes they are diesels, but depending if it is 6 inline cummins or cat the redline is much lower than the diesel V8 `s P.S./Dmax

If they can program a computer to turn your headlights on when it gets dark, dont you think they can program a computer to prevent excessive speed or something else from damaging a 10,000 dollar
engine?????????????
NO !
Head light replacement is inexpensive the engines long life is in my hands.
Computer or no computer.
Just compair how accurate the dic`s fuel mpg and fuel used is for most??
The computer controls the readings and most everyone has different readings. Some large and some small differences.
If you are in a huge downhill and the trailer keeps pushing you faster and faster and the engine rpm rises above 4800 or so, it will UPSHIFT to drop the engine rpm.

What if your already in 6th gear,then what???

If you want to play with gears/shifting that badly, buy a manual trans. :)

Why ?? when we can get a manual shift in the Allison.

ben

Thank you

My tranny is a long winded SOB.It loves 6th gear towing my towhauler,egt's were 1400*+ even starting up a hill,it didnt want to down shift,had to use the manual mode to lock in 4th.

This has been what I have been trying to explain(it did`nt want to down shift) and at 1400 + degrees (which is dangerous hi temps) the computer control should have downshifted before that hi of a egt temp,and it did`nt.

This is for those of you who do not quite understand a diesel engine. You can hold your foot to the floor and have your engine "sitting" on the govenor all day long. It will not hurt it, they are designed to work within these parameters. I am a heavy diesel mechanic and we run our engines at peak rpm's all the time. As long as it does not get hot you are not hurting it. Also, on our trucks, they are designed so you can not hurt it. The govenor keeps you from overspeeding the engine. It controls the fuel delivery, too much rpm's mean you will get less fuel so you do not exceed preset rpm limits. The trans has built in safegaurds also. Too many rpm's will get you an upshift, wheather you want one or not. It is pretty easy to understand; you are not going to hurt your engine or trans if you let it do its job.

You being a heavy diesel mech then you know the govenor is set well below the actual max rpm the engine is capable of doing.
Because it is always pedal to the metal.
A heck of a lot lower rpm setting than the diesel pick-ups are at.
The computer controlled diesel pick-up trucks Cummins,Dmax/P.S. lets you take it to the limit pretty close to destruction.

This has been what I have been trying to explain(it did`nt want to down shift) and at 1400 + degrees (which is dangerous hi temps) the computer control should have downshifted before that hi of a egt temp,and it did`nt.

HE HAS AN EDGE EVO. Of course is EGT's are going to be higher. With a stock tune, it will be fine, not gonna hurt anything as long as you stay within the spec'd trailer weight limit and do what it says in the manual, which is, tow/haul on and in drive.

As for you people who go wide eyed when yout put a pyrometer on your stock truck, who cares if the EGT's get high? Do you think GM didnt test their trucks with an EGT gauge in the real world towing tests???? For every one "diesel enthusiast" who puts gauges on their truck and is "knowledgable", there are 1,000 more people who dont know or even care what an EGT gauge is, and they do just what the manual says to do. Do their trucks blow up? NO!

ben

I dont know why GM even puts manual mode in. All it does is breed uninformed people who think they know how to shift better than the ECM and TCM that GM put so much R&D into programming and perfecting to operate in the most efficient and SAFEST way possible. :)

If you did not have the manual shift it would skip a gear when downshifting in most cases.
Sixth gear is actually overdrive if you didnot have the manual shift it would skip 5th and go into 4th gear,unless you can work the throttle just right

Skip a gear? It would skip TWO gears. The old IPC's only had D, 3, 2, 1. The manual mode was just because they didnt want a shifter with 2 feet of throw. 6th gear is actually overdrive? Oh really? So is 5th gear, FYI.

put it in drive, tow/haul on, and leave the freaking thing alone. This is what the allison transmission was bred for. NO you arent going to hurt the damn thing at 4000+ rpm,
I presume you know this with real life experances ???

Ive personally blown up and rebuilt more duramax and allison crap than you will ever know. I know damn well what the motors and tranny's will and will not take before you have a catastrophic failue. 4,800rpm is something they will take in stock form.



I dont care if "it doesnt feel right"
I guess until you toast a engine,or trash a trans ( I have) trusting all this so called computer controlled crap then you will continue believing what is on paper.


see above response.






or "well I drive a semi and they redline at like 1000rpm, so why should my duramax be any different, theyre both diesel engines arent they?".

Yes they are diesels, but depending if it is 6 inline cummins or cat the redline is much lower than the diesel V8 `s P.S./Dmax

no shit, I was being sarcastic.


If they can program a computer to turn your headlights on when it gets dark, dont you think they can program a computer to prevent excessive speed or something else from damaging a 10,000 dollar
engine?????????????
NO !
Head light replacement is inexpensive the engines long life is in my hands.
Computer or no computer.
Just compair how accurate the dic`s fuel mpg and fuel used is for most??
The computer controls the readings and most everyone has different readings. Some large and some small differences.

Whatever you say... The DIC in my truck is accurate, maybe I got a special one.


If you are in a huge downhill and the trailer keeps pushing you faster and faster and the engine rpm rises above 4800 or so, it will UPSHIFT to drop the engine rpm.

What if your already in 6th gear,then what???

Then that would mean you are going 190mph, jackass.

If you want to play with gears/shifting that badly, buy a manual trans. :)

Why ?? when we can get a manual shift in the Allison.

its not a "manual shift". Its a range hold function. Theres a difference. ;)

ben

HE HAS AN EDGE EVO. Of course is EGT's are going to be higher. With a stock tune, it will be fine, not gonna hurt anything as long as you stay within the spec'd trailer weight limit and do what it says in the manual, which is, tow/haul on and in drive.

As for you people who go wide eyed when yout put a pyrometer on your stock truck, who cares if the EGT's get high? Do you think GM didnt test their trucks with an EGT gauge in the real world towing tests???? For every one "diesel enthusiast" who puts gauges on their truck and is "knowledgable", there are 1,000 more people who dont know or even care what an EGT gauge is, and they do just what the manual says to do. Do their trucks blow up? NO!

ben

Not to argue,But that was stock...Not programmed,and no cat with a flow through muffler.It spiked 1550* before it shifted..But spiking at that temp wont hurt anything,but The ? is why does it like to sit in gear so dam long.I swear it will stay in 5th pulling a hills,the more you push the pedal,the more the egt's go up...wont shift down.Next time I go camping I will take my cam corder,and record what it does.

no shit, I was being sarcastic.

You sure fooled me.
Especially not by the way you wrote and explained on your first responce.

Whatever you say... The DIC in my truck is accurate, maybe I got a special one.

Mine is pretty accurate its others that have complained.


Then that would mean you are going 190mph, jackass.

I`ll leave this one alone.

its not a "manual shift". Its a range hold function. Theres a difference. ;)

Not with your explaintion on your first responce which was way off the wall I may add. I was refering to why shift all the time and have to use my left foot on the clutch ( it is the left foot for a clutch right ???) when I can manual shift the allison and rest my left foot and shift when
I FEEL IT IS NEEDED.
Noticed I said I as in ME, NOT YOU or ANYONE else.

I`ll leave the jacka$$ part for you to ponder with.



ben

Huggs and kisses!!!

Huggs and kisses!!!

are you insinuating I dont know what Im talking about when it comes to dmax's and allison's and what Im saying is all wrong? Maybe I need to make a signature that lists my trucks "mods" so people will give me a little credit?

ben

are you insinuating I dont know what Im talking about when it comes to dmax's and allison's and what Im saying is all wrong? Maybe I need to make a signature that lists my trucks "mods" so people will give me a little credit?

ben

You seem pretty proud on tearing up so many Dmax`s and Allisons that you have lost count.
It appears you don`t have a clue that you just might be doing something wrong tearing up all this stuff that is so called computer controlled bullet prof.

I started driving diesels in 1969 the last time I toasted a diesel engine was in 1973 it was plain ass stupidity on my part.
Kind of like someone else I know, not personally.
36 years later and I lost count after 2 million + miles, not one engine went down, except when it was worn out.
But I guess that does`nt count in you book that I might have a small clue on what just might be another good way of driving smart.
Conservatively speaking and driving, learning with the Smith System.

I`m sorry but you probably don`t know what the Smith System is, in short it is diesel driving education classes in hopes the professional truck drivers will have smarter driving habbits.
Most companies require drivers to take these classes and do refresher courses every 2 years in hopes they continue to have smarter driving habits.

Plus, I`ll most likely not be in a repair shop or doing repairs as much as you will.

And please do include in you sig all the trucks you did "mods" on and trashed out.:)
It will be interesting for all to know your true expertise.;)

Well then , Thank you.
The part you`all is missing what is on paper/print is not always the same as when your in real life situations and only has been done in perfect conditions.
I very well could be wrong but I feel with over 40 + years driving diesels and have been in just about every driving situation possible.
Testing and dealing with actual dynos for over the past 15 years, I have found the specs shown by all manufactures including GM, in most cases are not even close to what they advertise.
So I`m pretty comfortable with what I do and believe in, because I have been in real life situations, not on paper/printed one`s.

Yeah, you know what, your right. Let's not believe the engineers who built and designed the engine and tranny for these specific things, who have been testing them for a million years in REAL-LIFE conditions and situations, you must know more then them.

Plus, I`ll most likely not be in a repair shop or doing repairs as much as you will.

my truck has not been to the dealer since it was new...your point being?


And please do include in you sig all the trucks you did "mods" on and trashed out.:)
It will be interesting for all to know your true expertise.;)

what does "trashed out" mean??

"It will be interesting for all to know your true expertise". Most people here already knows my expertise regarding dmax engines and allison transmissions, but what would you like me to do to win YOUR approval? Would you like to see how I did that stupid 4x4 dash indicator LED trick years before you brought it up and thought you were so brilliant because of?

ben

not really trying to get in on this whole thing, but just because you have 40 years or what ever of driving diesels, doesn't mean you're a pro, on the D-Max that is, mainly because with all the features the D-Max/Alli combo has, it's not really like the old things you drove at all. I also noticed, it didn't really help your case when in your first or second post, you were already swinging and ready for a fight.

Holy Batman,page seven!

my truck has not been to the dealer since it was new...your point being?




what does "trashed out" mean??
I`m pretty sure it means breaking something


"It will be interesting for all to know your true expertise". Most people here already knows my expertise regarding dmax engines and allison transmissions, but what would you like me to do to win YOUR approval? Would you like to see how I did that stupid 4x4 dash indicator LED trick years before you brought it up and thought you were so brilliant because of?
drc`s truck is only 2 yrs old a 07.5 and no one has figured it out yet on adding a light on the new body style at least they have not mentioned it anyway.

ben

I`ve been reading both of yours so called knowledge on how to drive diesels wheither it is big rigs or pick-ups with cummins,p.s.,dmax, I would have to side with drc being the most knowledgable.
Like you said "ben" in one of your posts a diesel is a diesel no mater what`s its in.
My vote is with drc driving with common since and longivity.
Sorry "ben"

I`ve been reading both of yours so called knowledge on how to drive diesels wheither it is big rigs or pick-ups with cummins,p.s.,dmax, I would have to side with drc being the most knowledgable.
Like you said "ben" in one of your posts a diesel is a diesel no mater what`s its in.
My vote is with drc driving with common since and longivity.
Sorry "ben"

ROFLMAO - This guys had his hands in more engines and transmissions than I can think of.... he MADE - let me put that again - MADE a CUSTOM Operating system for the throttle pedal of a rock crawler by hand using efilive...He's got more how to's and tech questions answered than A L O T of people on this site.


Like you said "ben" in one of your posts a diesel is a diesel no mater what`s its in.

He was Quoting DRC - NOT aknowledging it....


Yes they are diesels, but depending if it is 6 inline cummins or cat the redline is much lower than the diesel V8 `s P.S./Dmax
Was his answer... :rolleyes:

not really trying to get in on this whole thing, but just because you have 40 years or what ever of driving diesels, doesn't mean you're a pro, on the D-Max that is, mainly because with all the features the D-Max/Alli combo has, it's not really like the old things you drove at all. I also noticed, it didn't really help your case when in your first or second post, you were already swinging and ready for a fight.

You must be very young and naive,just how many years does someone have to do something to qualify on knowing anything????
My last old thing truck before I retired was a 07 Kenworth C7 cat w allison auto.
Since 1985 I was rewarded a new truck every 2 years because I was one of the very few that broke down and spent time in the shop.
Plus I have owned personal diesel P.U. and towed trailers for over 15 years.
So I guess now I only qualify for the rockin chair,and to not make commonsince suggestions.

Last and final, when I started out talking towing rpm`s in this thread I said in "my opinion" these are good rpm ranges to be towing in.
Then the "bull" started from one`s that do not have much, if any towing experance, all they are concerned about is mpg,and showing dyno results on the lmm empty not towing. There would be a quite large difference in peak H.P.

Besides if the dyno results was doing a simulated towing it would have stated it on the dyno graf. This is also "old" knowledge.


Good luck and safe driving.

this thread has got me thinking - Would you be able to hold the pedal to the floor and drop it in reverse at 3200 rpm - or Neutral to drive?

Everyone has their opinion on driving and some give their opinions what has worked best for them.
But to continually bash someone on their opinion and experances which has work well for him many years, which I respect and listen,several claims make since and I agree.
This is really getting stupid.
Some of you need to get over it, and just make your suggestions instead of calling out and claiming people like drc knows nothing.
Crap he was just giving a suggestion to someone that was confused on towing.
What worked good for you, does not always work for another person,
Leave it like that and Get a life, and drop it.

this thread has got me thinking - Would you be able to hold the pedal to the floor and drop it in reverse at 3200 rpm - or Neutral to drive?
OH boy...let's save that for another thread :o:
Please - DON'T TRY THAT because someone said it can't hurt itself... roflmao!

Everyone has their opinion on driving and some give their opinions what has worked best for them.
But to continually bash someone on their opinion and experances which has work well for him many years, which I respect and listen,several claims make since and I agree.
This is really getting stupid.
Some of you need to get over it, and just make your suggestions instead of calling out and claiming people like drc knows nothing.
Crap he was just giving a suggestion to someone that was confused on towing.
What worked good for you, does not always work for another person,
Leave it like that and Get a life, and drop it.

Me and Ben are stating fact, that guy asked a question about what his truck would factually handle... Not a personal opinion.
The only reason i corrected anything is the guy was plain wrong on some of his comments, i just went back and wanted to let him know there was an easier way of doing things.
He started being jack ass and well, I followed. It was fun though :D

I don't claim to know everything, I do know the above though, telling me I'm wrong when I've DONE it - in THIS PARTICULAR truck is stupid.
It's not his old c7 - telling people things that's not true someone's going to correct you, and with his attitude I have a feeling you'll be seeing it alot more in threads dealing with him.

If he decides (or anyone else for that matter) his driving style is what he posted as such, BY ALL MEANS do it! I only have a problem with people claiming it's X Y and Z and not knowing what they're talking about.... I went outta my way and posted INFO from ALLISON for the guy and I'm still wrong. LOL

this thread has got me thinking - Would you be able to hold the pedal to the floor and drop it in reverse at 3200 rpm - or Neutral to drive?

nothing would happen till the rpm's came to a idle

Get back on track with RPM's and OP question. PM your personal differences with other members.

Thanks fellas. ;)

You must be very young and naive,just how many years does someone have to do something to qualify on knowing anything????
My last old thing truck before I retired was a 07 Kenworth C7 cat w allison auto.
Since 1985 I was rewarded a new truck every 2 years because I was one of the very few that broke down and spent time in the shop.
Plus I have owned personal diesel P.U. and towed trailers for over 15 years.
So I guess now I only qualify for the rockin chair,and to not make commonsince suggestions.

Last and final, when I started out talking towing rpm`s in this thread I said in "my opinion" these are good rpm ranges to be towing in.
Then the "bull" started from one`s that do not have much, if any towing experance, all they are concerned about is mpg,and showing dyno results on the lmm empty not towing. There would be a quite large difference in peak H.P.

Besides if the dyno results was doing a simulated towing it would have stated it on the dyno graf. This is also "old" knowledge.


Good luck and safe driving.


ahh just as I suspected...you are one of those old timers who thinks he knows and has seen it all just because hes been stumbling around in the dirt a couple more years than the person hes arguing with. Great arguing tactic. Well Im older so therefore I automatically know more about everything in the world, so bite me! :p:

this thread has got me thinking - Would you be able to hold the pedal to the floor and drop it in reverse at 3200 rpm - or Neutral to drive?

Im a stupid young whippersnapper, so in that case I dunno what would happen? Ask DRC, he seems to know whats up with everything diesel.

ben

I've had my LB7 to almost 5000rpm a time or two :rolleyes:. They will darn sure run down the track with a sled it tow at 4000rpm.

One more negative post calling someone out and this is closed and warnings will be issued. Ive already asked you guys once and now your showing disrespect by spouting off again. Im trying to keep this open for FACTUAL information and not insulting each other.

I drive and tow more conservative than most do, its what I`ve done for years.
I am not a aggressive driver.

Also I never stated anything on what I thought was max rpm`s, I stated what rpm`s I feel is a good range to run towing and not chance pushing any limits.

Most defintly a few members read wrong into what I originally answered with this thread, and blew it way out of text.

If your a aggresive driver your probably right with limits.
I am not going to push it to find out.
If you want to be conservative, I`m pretty sure I`m very close to being right.

Besides this more than likely will be my last truck and I would like it to last.

One more negative post calling someone out and this is closed and warnings will be issued. Ive already asked you guys once and now your showing disrespect by spouting off again. Im trying to keep this open for FACTUAL information and not insulting each other.

I'm the OP and in that first post the only question I actually asked was what was the actual redline on the LMM. That info was pretty well laid out in the first couple of pages along with some other pretty good info and advice that I can take or leave. The last few pages deteriorated into a totall pissing match that I don't even want to get into. I'd like to say thanks for the info and please shut it down.

Pulled my nearly 10,000 lb bumper pull toyhauler through the mountains over the weekend and was impressed with the truck. Found out I prefer using manual shifting over auto when Tow Haul Mode is engaged. Auto mode simply allows to much shifting when in the constant up and down terrain and on steep down hill terrain the tranny can be forced into what I believe is to low a gear causing the RPMs to go way to high for my comfort level. I thought I saw well over 4000 RPM a couple of times when braking prior to a downhill turn. Manual mode lets me control the gear and when I need to slow a little more the truck and trailer brakes are more than enough to control my speed. Just what is the redline on the Duramax anyhow? I can’t find any marks on the tach so apparently GM doesn’t want me to know.
Overall I was very pleased with pulling a heavy load through the mountains. I think my 7.3 PSD had a little more power but it had a Edge Evolution Tuner installed so that’s not a real comparison. My Duramax is rated a lot higher in horsepower than my PSD was even with the tuner installed but it just doesn’t seem like it. I love the Allison though. I never had a Tow Haul mode in my Ford and always hated pulling down steep hills because when you hit the brakes the torque converter would unlock and make it harder to control speed. Tow Haul Mode and 6 speeds is going to spoil me.
Do you have the edge evolution on this truck to? In level two they have a turbo brake feature that might change the way you drive also...

I'm the OP and I'd like to say thanks for the info and please shut it down.

Done.