Just bought a 92 454 SS and need to change the trans (4L80E) fluid. I read that GM is saying to use Dexron 6 in the older trucks. Can anyone verify this. Also is Dexon 6 compatible with Dexron 3?

Thanks

honestly i would stay with DEX III. DEX VI could possibly deteriorate your seals and gaskets. if im wrong someone please chime in

Dex VI is suppose to be compatible with all other Dextrons, so you should be fine. If you can find III, IV or V, then use that and you are 100% in the clear.

Now to note: If you don't know the service history of the trans, I would not recommend servicing it. New fuild on an old un-taken care of trans will wash that puppy clean in no time and it will be rebuild time. Seen it many times over. ;)