Last Friday I had my Allison at the Chevy Dealer for a tranny flush, internal filter chnage, spin-on change and refill. They refilled it with Dexron VI. Is Dexron VI ok for my '02 Allison 1000? I've done a search here and cannot find a specific answer to my question................SWH...

Yes, that is the new fluid that GM recommends for the trans.:)

I think I answered you in another post, but I'll reply here too.

It's my opinion that DEX VI is not compatible with your 02 Allison, based on a link I'll provide at the bottom.

The link from Allison speaks specifically to the fluids: TES-295, DEX VI and TES-389. There is clearly a serial number delineation showing the compatibility of Allison transmissions with DEX VI. Some Allisons are not compatible at all; others are only compatible after a cut-off.

I would suspect that your's does NOT make the cut-off, because your truck/trans is much older than the cut-off. Perhaps an Allison dealer/service center could tell you why. Maybe it's the seals, clutch material, who knows? If it were me, and the Chevy Dealer put DEX VI in an Allison that was not intended for it, I'd have them do one of two things. Either give you a WRITTEN warranty stating that DEX VI will not harm the Allison, and that they will cover any damages incurred including labor, OR get it out right now and replaced with a DEX III based fluid, which includes TES-295 and the clones. You're out of the regular warranty period; perhaps the TES-295 clones would be a good choice. Perhaps print out the following link, take it to the dealer for "information sharing" and if you ask nice, they should be agreeable to swapping out the fluid. If not, I'd consider to giving them any more of my business if I were you.

DEX VI is a vastly improved fluid over it's predecessor (DEX III). But, GM made a blanket statement about backwards compatibiltiy regarding all the GM transmissions, and they sort of left a grey area when it comes to Allison transmissions. Allison specifically addressed the question when GM would not.

Caveot Emptor.

Here's the link. http://www.allisontransmission.com/servlet/DownloadOnDemand?ApplicationID=155&DownloadID=5&Preview=1

I think I answered you in another post, but I'll reply here too.

It's my opinion that DEX VI is not compatible with your 02 Allison, based on a link I'll provide at the bottom.

The link from Allison speaks specifically to the fluids: TES-295, DEX VI and TES-389. There is clearly a serial number delineation showing the compatibility of Allison transmissions with DEX VI. Some Allisons are not compatible at all; others are only compatible after a cut-off.

I would suspect that your's does NOT make the cut-off, because your truck/trans is much older than the cut-off. Perhaps an Allison dealer/service center could tell you why. Maybe it's the seals, clutch material, who knows? If it were me, and the Chevy Dealer put DEX VI in an Allison that was not intended for it, I'd have them do one of two things. Either give you a WRITTEN warranty stating that DEX VI will not harm the Allison, and that they will cover any damages incurred including labor, OR get it out right now and replaced with a DEX III based fluid, which includes TES-295 and the clones. You're out of the regular warranty period; perhaps the TES-295 clones would be a good choice. Perhaps print out the following link, take it to the dealer for "information sharing" and if you ask nice, they should be agreeable to swapping out the fluid. If not, I'd consider to giving them any more of my business if I were you.

DEX VI is a vastly improved fluid over it's predecessor (DEX III). But, GM made a blanket statement about backwards compatibiltiy regarding all the GM transmissions, and they sort of left a grey area when it comes to Allison transmissions. Allison specifically addressed the question when GM would not.

Caveot Emptor.

Here's the link. http://www.allisontransmission.com/servlet/DownloadOnDemand?ApplicationID=155&DownloadID=5&Preview=1

I appreciate your percerverence informing me of your "opinion" on this subject in both threads and to that end I did some investigation. I talked to the local Allison/Detroit dealership service advisor and he called his head office to find out the straight poop. He already new and was confirmed by his head office that Dexron VI is fully compatible (reverse compatible) with all Allison 1000 series trannies that have been in the GM pickup line since the model year 2001. This is now the fluid of choice by GM and will continue to be for the foreseeable future. While he did tell me that the Castrol synthetic is a better choice he said that Dexron VI is a partial synthetic and will in no way harm any of the Allison 1000 series trannies. He went on ti tell me that a lot of the internet jibber jabber is bogus. After my conversation wiht him I called the dealer who did my flush and they also insured me that Dexron VI will be the standard fkuid for all auto tranny servicie/flush procedures. I also have come to the conclusion that since this is the new standard fluid installed in GM products then they would not just use it on a whim!! If they say it's a "good to go" item then that's good enough for me........................SWH...

Sounds good to go, then. DEX VI is a much better fluid that conventional DEX III. It's viscosity retention, and resistance to oxidation are roughly double the previous fluid, making it much more stable.

Still, I don't understand why Allison would publish a 15 page document, that on page one, specifically states there is a serial number cut-off regarding DEX VI useage in 1000 series applications. And DEX VI is not completely backwards compatible, because on that same page, Allison flat states not to use it in some of their tranmissions, at all, whatsoever. That doesn't include our 1000 series, but still, it's incorrect to state that DEX VI is completely backwards compatible in ALL DEX III applications. DEX III (and the Mercon equivilant) is used in all kinds of applications, and that doesn't even stop at transmissions. It is used for power steering fluids, hydrualic cylinder fluids, etc. GM made a huge blanket statement that flat isn't true for ALL applications.

Bottom line is this: if you're content, that's what's important. At least you got involved, asked questions, and came to a conclusion that you're satisfied with.