Re: Dextron III / IV or Synthetic ATF
 

While there may be synthetic versions of Dex6 , the factory fill is not synthetic . The additive package that is in Dex6 defines the anti-wear , foaming , and friction characteristics. Dex6 synthetic or Dex6 mineral based fluid will have the same friction profiles . That is the definition of Dex6 .

Re: Dextron III / IV or Synthetic ATF
 

Dexron HP fluid, which is what GM is now using in the 8 speeds is fully synthetic. Some of the the 8 speeds that were filled with Dex6 are having tcc shudder issues and they are having us flush and refill with the HP fluid. I fixed a very low mileage 17 Canyon with this procedure. The GM part number is 19300536. Mobil 1 also has a version. Stuff is pretty pricey though.

Re: Dextron III / IV or Synthetic ATF
 

Allison Transynd, in my race cars and daily drivers. None better!

Re: Dextron III / IV or Synthetic ATF
 

Curious about Allison Transynd. Allison recommends it for all of its transmissions and requires it on newer 3000 and 4000 series models. I have one of the older 3000's and can use either Dexron or Transynd. I have never had a problem with Dexron 3, if I change it once in a while.

I had planned to change to the synthetic, but a truck shop specializing in heavy duty Allisons told me not to waste my money. They said they don't use the synthetic because it is so expensive and they haven't seen any benefit.

What gives with all of these really expensive ATF's? The stuff required in the new Jaguar's is $20.00 or more a quart.

Thanks,

Loren

Re: Dextron III / IV or Synthetic ATF
 

Transynd is the same as TransMax , which is a Dexron synthetic made by Castrol. It is excellent .

Re: Dextron III / IV or Synthetic ATF
 

Normally, asking your transmission builder is best.

Re: Dextron III / IV or Synthetic ATF
 

Mobile 1 also has Allison approved Mobile Delvac Synthetic Trans fluid TES-295 #112810. Better blending stocks than Castrol.
I agree with Ed, your trans builder knows...

Re: Dextron III / IV or Synthetic ATF
 

At 20$/qt, how many qts go in an Allison 3000 series transmission?

StickBBF

Re: Dextron III / IV or Synthetic ATF
 

The Jaguar transmission fluid is a complete joke. I said $20.00 but I think it is much more than that from the dealer. The Jaguar transmission requires ten to 14 quarts.

The Allison 3000 requires about 28 quarts depending on the sump size. Allison says to change it every 75,000 miles.

The Allison 4000 requires about 40 some quarts depending on the sump size. Again every 75,000 miles.

If Dexron is used it is supposed to be changed every 25,000 miles. When I do that, it looks the same as the stuff I started with. Not dirty or anything.

Filters (two large ones) are very high quality and very expensive, never seem to get dirty.

The whole thing seems odd to me but rebuilding one of these things is VERY expensive, so I just bite the bullet. Just wish I knew more about transmission fluids.

Loren

Re: Dextron III / IV or Synthetic ATF
 

I have been reading a lot about them.
Cannot get a straight answer if they are all made by one source.
Then marketed under different names.
Then the confusing specification information between them to make them look different.

What I do see is that Synthetic behaves differently. Able to take more heat and offer better protection.
Synthetic different grip and lubrication properties over standard Dexron III/IV.
So much so that Synthetic lasts 3 times as long.

Wonder who has done a study on Dexron after 25000 mile change.
What do the properties look like after use?

There is Amzoil vs Standard, Amsoil vs Royal Purple, vs Redline

This was a fun youtube video.
https://www.youtube.com/watch?v=dntD3XmI8DM