I bought a truck a year ago with the 6 speed auto and i am wanting to change the trans fluid, is it easy to do it myself, do i replace just outter filter or is there a inner filter as well? should oil be drained or flushed and how if flushed? thanks in advance

I would change the spin on filter and drain the fluid and refill. Do not do a flush. If you want to get all the old trans fluid out, do a search on here for the HOOT method.

Drain pan, change spin on and clean magnet, replace drained fluids with Allison Transynd.

k thanks, by just draining it will leave a bit in right i take it ? wat about internal filter

allison says internal filter change not required ever unless trans is overhauled

Changing the internal filter is pointless unless doing an overhaul. Life-long service can be attained via the drain/fill method with external filter changes. That is the official Allison position.

The external filter and magnet are the primary elements used in catching unwanted contamination. The internal filter is there for blocking large "chunks" of material from being sucked up should a catastophic event occur. The internal filter serves no purpose in daily operation. If the spin-on filter and magnet won't catch it, I can assure you the internal filter will NEVER catch it. The internal filter will not stop what the external let pass.

Many people drop the pan and change the internal filter for "peace of mind". I see zero logic to this. Further, think back to the days when we HAD to drop a pan to change the only filter there was; what a mess! Now, Allison has seen fit to install a drain plug, and an external filter, all in the name of easy service. And yet, some people still want to drop the pan. Go figure ...

k thanks, by just draining it will leave a bit in right i take it ? wat about internal filter

Using the pan drain & refill method.....(if my numbers are correct), the Allison holds a total of 12.7 qts. of ATF. Pulling the drain plug on the standard depth pan drops ~ 7.75 qts. Then after the first pan drain & refill you will have 61% new fluid, after the second it will be 85%, the third will bring it up to 94%, 98% on the fourth and 99% on the fifth. Allison says two pan drains (85%) is plenty for HD service with Transynd.

DEWFPO

Changing the internal filter is pointless unless doing an overhaul. Life-long service can be attained via the drain/fill method with external filter changes. That is the official Allison position.

The external filter and magnet are the primary elements used in catching unwanted contamination. The internal filter is there for blocking large "chunks" of material from being sucked up should a catastophic event occur. The internal filter serves no purpose in daily operation. If the spin-on filter and magnet won't catch it, I can assure you the internal filter will NEVER catch it. The internal filter will not stop what the external let pass.

Unfortunately, not all Allison dealers, or at least parts people, understand this. I was buying some ATF and a spin-off at a local shop last week, and the young guy behind the parts counter was trying to tell me it was imperative that I change the internal filter at 80k miles -- he actually brought one back with him along with the other parts I'd requested. He claimed the spinoff was just a bypass, and didn't really do anything. He was probably just trying to make a sale, and/or was a hyperactive but unknowledgeable counter person (really wanted to talk D/A but didn't seem to know a lot about them!). Thanks in large part to advice rendered here, I knew he wasn't telling me right, so I politely declined and left with my Delvac and spin-off.

On this note, is there any reason to wait between drains to get all the old fluid out? I imagine complete mixing of new and old fluid occurs quickly after driving. I'll do my first drain this weekend. Should I do my second drain in a week or two after that, or wait for a few thousand miles?

If your current fluid is in good shape, then only one change is necessary. There is a sticky I had placed at the top; read it over and you'll see the maintenance schedule from Allison.

Further, the spin-on filter is not a "bypass" filter, although it does not see full system flow. It filters flow going to the valve body, IIRC. That is by far the most important portion to protect. Here are the criteria from the WIX website for that filter (other brands are very similar):

Part Number: 57701
UPC Number: 765809577015
Principal Application: Allison Trans Filter - Chev/GMC PU w/ 6.6L Diesel + 8.1L Vortec (01-10)
All Applications
Style: Spin-On Transmission Filter
Service: Transmission
Type: Full Flow
Media: Paper
Height: 3.000
Outer Diameter Top: 3.065
Outer Diameter Bottom: Closed
Thread Size: 3/4-20
By-Pass Valve Setting-PSI: 8
Beta Ratio: 2/20=15/25
Burst Pressure-PSI: 780
Max Flow Rate: 7-9 GPM
Nominal Micron Rating: 15

Gasket Diameters
Number O.D. I.D. Thk.
Attached 2.750 2.460 0.390

As you can see, it has a reasonable BETA ratio, but nothing like a bypass filter. It is a full flow filter specifically designed for the Allison application. It is used in a partial flow path, but it does filter all the oil eventually. It is good enough that Allison gives it 50k miles in "normal" service, and 12k miles in "severe" service.

Here is the Allison link; check out page #6:
http://www.allisontransmission.com/servlet/DownloadOnDemand?ApplicationID=155&DownloadID=5&Preview=1

It specifically calls out the spin on changes at 10k miles for the initial change, then the intervals are at 50k or 12k depending upon severity. Note the internal is ONLY listed at overhaul.

People can, and do, change the internal. But it's a waste of time and money. Fine for them if it makes them happy. No one is "neglecting" their tranny by not doing the internal filter. No one is "improving" the lifecycle if they choose to do the internal.

'Nuff said.

On this note, is there any reason to wait between drains to get all the old fluid out? I imagine complete mixing of new and old fluid occurs quickly after driving. I'll do my first drain this weekend. Should I do my second drain in a week or two after that, or wait for a few thousand miles?

If your current fluid is in good shape, then only one change is necessary. There is a sticky I had placed at the top; read it over and you'll see the maintenance schedule from Allison.

I believe Newton is right- however I guess it depends if you are switching fluids (I am under the impression you were talking about switching to syn, etc.). If you are then I would drive it a couple of thousand after dropping it the first time and drop again- if you are just doing routine maint. and replacing with regular Dex III or VI the Newton is def. dead on and one dump is good enough!!!!

I like using the Allison external filters. Read several posts here about the holes in the cheaper filters not lining up well with the magnet & actually blocking some of the flow. The Wix filters are a perfect fit & are great filters also. Found the Allison brand at a local Allison service center for about $9. Dealer wants about $40 for the same filter. Some of the vendors on this site has a good price also for the factory type filter.

So if i want to change to delvac synthetic i should change it twice or what? it is stupid that it only drains 61% out by pulling the plug. I dont know whats in it now so whats the right way to do it. Money isnt a issue i just want to get as much life out of the trans as possible, i would think this delvac stuff should be the way to go.

So if i want to change to delvac synthetic i should change it twice or what? it is stupid that it only drains 61% out by pulling the plug. I dont know whats in it now so whats the right way to do it. Money isnt a issue i just want to get as much life out of the trans as possible, i would think this delvac stuff should be the way to go.


I would do exactly what you said.

I believe Newton is right- however I guess it depends if you are switching fluids (I am under the impression you were talking about switching to syn, etc.). If you are then I would drive it a couple of thousand after dropping it the first time and drop again- if you are just doing routine maint. and replacing with regular Dex III or VI the Newton is def. dead on and one dump is good enough!!!!

Yeah, I'm "switching" the old fluid out for Delvac TES-295, as I just bought the truck in February and don't know what is in there. I'll drain the pan this weekend and then give it another month and do it again. Thanks.

I like using the Allison external filters. Read several posts here about the holes in the cheaper filters not lining up well with the magnet & actually blocking some of the flow. The Wix filters are a perfect fit & are great filters also. Found the Allison brand at a local Allison service center for about $9. Dealer wants about $40 for the same filter. Some of the vendors on this site has a good price also for the factory type filter.

Wow. I paid $7.88 for the spin-off at the Ally dealer. $33 and change per gallon of Delvac.

When I changed oil I removed the cooling tubes and with very low air pressure, blew the oil from the cooler. Then I started the engine and blew the oil from the torque converter. I got very close to 12 quarts from it. Replaced the spin on filter and filled it with Transyn at about $30/gallon from Allison Dealer. I read their change interval to say 75,000 miles severe duty, and 150,000 miles normal duty. For me that is a very long time.

it is stupid that it only drains 61% out by pulling the plug.

Why does that sound "stupid" to you? Pulling the plug on the pan does not drain the torque convertor, and the TQ does not drain when the engine is shut off.

DEWFPO

well when you change motor oil you probly get 95% of it out. Seems dumb only replacing a little over half with new oil. Ill just do it twice i guess

ok no one around had the mobile stuff....NAPA store looked it up on computer and gave me castrol dexron VI, its a sythetic blend. Says for use in general motors vechiles on label, and also gm hydra matic trans....should i use this stuff or take it and back and look for something better??????? Truck has a fram filter on it when i got it but i picked up a AC delco one from gm...45 bucks.

which filter did you pay $45 for?

ac delco spin on trans filter

so anyone know if the castrol dexron VI synthetic blend stuff i got is recommended....want to find out before i go ahead and do it.

I would recommend that you go to Allison.com and read what they have to say. They are the only ones here that are putting their money where their mouth is. Using an unauthorised oil may void your warranty. It's 100,000K and 5 on your truck I think that the '06 may have come from the factory with Transynd in it. The service intervals are way out there. As far as draining the torque converter is conserned, pulling the plug does not drain it, but cranking the engine with the cooling tubes removed does. I'm not sure that it is worth the effort however. BTW there is nothing new or novel about a 60%to 80% fluid change in an automatic transmission. Its been that way for over 50 years and if most people did that, the transmission would out live the engin.

so anyone know if the castrol dexron VI synthetic blend stuff i got is recommended....want to find out before i go ahead and do it.


DEX 6 is harmful to seals in some 06 trannys. Use a TES 295 Allison approved fluid and be done with it.

Oh and the Allison never left a GM factory with Transynd.

DEX 6 is harmful to seals in some 06 trannys. Use a TES 295 Allison approved fluid and be done with it.

Oh and the Allison never left a GM factory with Transynd.

Most of the 2006's do not have the Dex6 compatible seals. GM dropped the fluid change on Allison and it really wasn't until the summer of 2006 (with the 2007's) that the new seal material made it into full production.

The Allisons in the 2006 and 2007 Classics were filled and tested at the transmission plant using DEX3, the truck plant added DEX6 to fill the coolers and lines to top off. Only the 4500 and 5500 Medium Duty trucks got TranSynd. The NBS 2007 and later are filled with conventional DEX6.

So the moral of the story is Crafty to use TES 295 and be done with it correct?

ok no one around had the mobile stuff....NAPA store looked it up on computer and gave me castrol dexron VI, its a sythetic blend. Says for use in general motors vechiles on label, and also gm hydra matic trans....should i use this stuff or take it and back and look for something better??????? Truck has a fram filter on it when i got it but i picked up a AC delco one from gm...45 bucks.

Go to Allison's website and do a dealer search -- based on those prices, it would be worth your while to find an Ally dealer! I don't think most auto parts stores are going to have TES-295 fluids, and if they do, I bet they're gonna be pricey.

I got my Mobile Delvac from an Allison dealer/repair shop. Just over $8/quart ($34/gal), which makes it comparable in price to the synthetics found in chain parts stores, ie, the Castrol DEXVI mentioned here. The Delvac will be a better choice for the Ally from everything I've read. And the spinoff filter was only $7.97 at the Allison dealer.

I drained and filled on Saturday. As others have mentioned, it shifts smoother now, even though I wouldn't have thought it possible before the change. I'll do it again in a month or whenver I'm ready to plunk another $70 for 2 gallons of Delvac.

So the moral of the story is Crafty to use TES 295 and be done with it correct?
Yes, TES-295 certified fluids are the best for use in any year Allison...

The reason i went with this stuff is i can buy it local and according to the net this was the right stuff to use for my year of truck (according to the dealer) Ill run it awhile and then when i get to the city ill buy the right stuff and do it again.