My daughter got T-boned recently. She's fine, but her '96 Civic LX was a total loss. I've got several quarts of Honda AT fluid left from a case purchase. Would it be prudent to use in the '97 4-cylinder Camry that replaced the Civic?
Use it in the Toyota. Honda back spec the Z1 to some of their Dexron vehicles to cure issues. Think of it as an improved Dexron, since that is what it really is.
They did. However, Honda did testing of the friction materials to ensure full compatibility. Toyota has never tested their friction materials with a Z1 type fluid so using Z1 in a Toyota AW unit spec'ed for Dexron would be playing Russian Roulette. It may be fine in the short run, but there are always the unseen, possible long-term effects. It's up to you if you'd like to assume that risk, but I'd rather not.
No, no russian roulette. ATFs are very similar. The big push is in smoothness through friction modification, and long life through better additives AND/OR better base oils.
And, the thread starter didn't say he was going to do a 20qt flush either. 1 or 2 drain refills, with almost any ATF, in a well maintained transmission isn't going to cause issues if the fluids are similar.
The Z1 should work well in ANY dexron II or III application. Its only weakness is the friction modification level, higher than Dexron. It'll shift smoother, and a very tired worn out tranny might slip, but that could happen with any new ATF.
Transmissions aren't way different. They have gears(various types), clutches, and seals. I would think that the Z1 would protect better because of the differenct gear arrangement, and that the Z1 needs to survive in a CVT.
Here are possible long term affect of using the Z1 in your Toyota. It might last longer, shift smoother, and the insideds might clean up some, when compared to a Dexron III!
I've done some OEM crossfilling and haven't experienced short or long term issues. You'd be surprised how well ATF+4, SPIII, D-matic, TIV, and Z1 work in 'other' transmissions.