allison fluid....which is it?

[Trouttrooper]

Well, I've done some searches and I'm still not confident with what I can use.

 

 

My owners manual says Dexron III with "approved for H-Specification".

 

Dealer says no no no Dexron III, gotta buy GM fluid (part number blah blah blah). I told him my manual said Dex III and his reply was "we use our own stuff". He made it sound like DexIII would be very bad for the tranny.

 

Allison says Transynd fluid.

 

 

I don't want to use the wrong stuff, but I also don't want to spend any more money than needed. I've got Dexron III in my garage but I can't find anything that talks about "H-Specification". I don't see anything on the bottles in the stores either. What the heck is "H-Specification"????

 

Any good internet sites selling transynd??

[95Sierra2500]

The dealer is always going to try to sell you something that has the GM badge on it, because they get their 25-50% markup on it. If they just sell you DexIII (which is what theirs is, it just doesn't say it), then they don't get the markup. I'd suggest going with what the book says, though, because it is what the engineers who designed it (or at least picked what would go in the truck) suggest, and I'd trust them a little more than some high school grad at the parts counter.

[Trouttrooper]

The dealer is always going to try to sell you something that has the GM badge on it, because they get their 25-50% markup on it. If they just sell you DexIII (which is what theirs is, it just doesn't say it), then they don't get the markup. I'd suggest going with what the book says, though, because it is what the engineers who designed it (or at least picked what would go in the truck) suggest, and I'd trust them a little more than some high school grad at the parts counter.

 

Guy behind the counter was older than me (I think I found a gray hair the other day ). It was my understanding that DexIII was the same as the GM fluid.

 

Normally I'd agree in going with what the book says but I've just gone through a bunch of info about how my '91 Jeep owners manual has a misprint for the tranny fluid and will shorten the life if you put in what the book says.

 

I'm still trying to figure out what "H-Specification" means

[dewfpo]

GM had Allison use dino DEXIII in our 05's. So DexIII is fine, synthetic DexIII (M1 ATF) is even better, and even better than that is Allison's Transynd. (DEXIII is being superceded by DEXVI but DEXIII works just fine.) 06's up spec DEXVI

 

DEWFPO

[Trouttrooper]

Well, I figured out the H-specification thing. Just an upgrade that DEXIII had a few years ago. In other words all DEXIII on the shelves nowadays are "H-Specific".

 

Sounds like DEX VI will be replacing it anyway so probably just a moot point in the near future