Transynd vs Dexron VI

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

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

How many years old/how many miles on it?

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.

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.

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.

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

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.

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.