I just installed a tranny temp sensor in my ZF6 and needed to add a little gear oil. The stealer charged $21+ per quart -:t

I stopped at a Mobil oil shop and they are checking but believe it is the same as 75-90 gear oil for less than $8 per quart. It looks the same, smells the same and the bottle is similar.

I cannot believe GM produces their own oil :rant: .

The closest thing to the factory fill would be syn. dexron. The fluid came by had from dmaxallitech for $35 a gallon I think. I paid 13.00 per quart from local dealer.

maybe try the local ford dealer? the SD's have the same 6 speed tranny don't they? [99% sure it is a zf6]

Garentee GM doesn't produce their own oil. They contract it out to someone, have GM stickers put on the bottle, and rip you off. If I'm not mistaken the ZF's run synthentic ATF (Dexron III).

Castrol is the maker of TranSynd. Castrol Syntec Full Synthetic transmission fluid is Castrol's version. I use that but it can be hard to find. Some Autozones carry it while others don't. Same is true for about every auto parts store.

I posted this earlier today but it seems to be lost. . . .

AMSOIL claims TransSynd is made by Casterol. Do a TransSynd search on Google and you will see a lot of AMSOIL posts. about the comparison with their ATF. I even saw a chart that showed exactly the same test results.

What I don't understand is whether what they are writing about is the same TransSynd that we use in ZF6? :help2:

Deadeye - as far as I know, transynd is transynd...