Transynd vs Dexron VI

That is a question I would ask Allison. Better than our opinion.

Suspect it can be used, but do not know how it affects recommended change intervals.

I have always just bought a 5 gallon PAIL of Transynd and the Allison filter kit from our local Allison Dealer. The pail leaves you with one quart left over and is less $$ than buying individual gallons/quarts.

Allison ONLY recommends transmission fluid that is TES-295 approved. Several manufacturers meet this spec. I would not use any fluid that does not say that it meets the Allison TES-295 specifications. The older transmissions did come with a non-295 Fluid, probably Dex III in your case, but why go with any inferior fluid when Allison now recommends a fluid that meets TES-295 in their older transmissions. You do not have to buy Allison fluid if you don't want to give them the money but I would definitely recommend buying the newer spec fluid from someone, anyone, instead of using an older fluid. Saving a few bucks on a transmission that can cost $5000+ to repair just doesn't make sense. BP, Castrol, and others make the TES-295 fluid that you need. Try to find one on sale and use the right, most recent fluid, instead of using a fluid that Allison abandoned many years ago for their transmissions.

I am almost sure your 2004 Allison has seals that are not compatible with Dextron VI but they are compatible with Transynd.

Dextron VI post #63

What makes you think your transynd is bad ? I’d have it tested and change the filters .. in mh use I doubt it will wear out. Your call but it’s expensive and if it test ok I would use it , some won’t and are only time centered
I was told they are comparable but must be changed if used frequently.

Stick with what Allison recommends, the transynd. When I bought my LBZ first thing I did was change to transynd. They recommend to change ever 100k so it’s not much as far as cost goes.

RCMAN46 wrote:
I am almost sure your 2004 Allison has seals that are not compatible with Dextron VI but they are compatible with Transynd.

Dextron VI post #63

I may be wrong as I did not notice it was an Allison 3000 but what I have indicated is true for a 2004 Allison 1000.

If the question is "should I change the fluid":

How many years old/how many miles on it?

Allison ONLY recommends transmission fluid that is TES-295 approved.

The Diesel Supplement manual for the 2018 D/A recommends Dexron VI above temps of -40 F. Below that it specifies TES 295. That holds true for 2013 and up model years

Charlie D. wrote:

Allison ONLY recommends transmission fluid that is TES-295 approved.

The Diesel Supplement manual for the 2018 D/A recommends Dexron VI above temps of -40 F. Below that it specifies TES 295. That holds true for 2013 and up model years

So basically anyone that has an Allison transmission anywhere other than the frozen arctic should not use Transynd TES-295 rated fluid, since most of the lower 48 has temps above -40 F. Only use TES-295 for temps less than -40 F. I think you need to reread your source. :B

rgatijnet1 wrote:

Charlie D. wrote:

Allison ONLY recommends transmission fluid that is TES-295 approved.

The Diesel Supplement manual for the 2018 D/A recommends Dexron VI above temps of -40 F. Below that it specifies TES 295. That holds true for 2013 and up model years

So basically anyone that has an Allison transmission anywhere other than the frozen arctic should not use Transynd TES-295 rated fluid, since most of the lower 48 has temps above -40 F. Only use TES-295 for temps less than -40 F. I think you need to reread your source. :B

You need to reread my quote. I quoted the manual and it's recommendations. Neither the manual or I said NOT to use Transynd. My source is from GM page 125 of the Duramax Diesel Supplement. It has been in that manual from when I bought my first 2006 GM diesel and 2013 and 2018.

" DEXRON®-VI Automatic Transmission Fluid.
Allison Transmission Only: For areas where ambient temperatures are
below -40°C (-40°F) use Synthetic Transmission Fluid approved to Allison Transmission specification TES-295 (GM Part No. 12378515, in Canada 88900701)."