[Chiefkey]

I know this has likely been asked and answered many times before, I just can't seem to find it in a search. What is the best available brand of gear lube and trans fluid to use in my rebuilt tempestorque transaxle ? also what about Synthetics vs. old school ?
Thanks,
JK

[mechanickeith]

The crossover to todays conventional fluids is Mercon/Dexron ATF. For the diff, it says 90 weight gear oil. I run 75-140 synthetic in my diff. I figure the much hotter weather here in Phx. Az, it wont hurt.

[mgarblik]

The one I did a couple days ago, the customer provided the fluids. He used blue bottle, Valvoline Dex/Merc which said it was backwards compatible to original Dexron. It is a non-synthetic. The differential oil he brought was also non-synthetic Valvoline 80W-90. Just under 2 quarts in the differential and 9 quarts in the trans section. Service manual says 10 quarts on a dry rebuild but it had some in the converter from the rebuilder. I think the shift feel was excellent with that fluid and the way the valve body, governor and modulator were tuned. Very quick, crisp shift. Not harsh. Type F would produce a much more harsh shift if that's what your after. I was nervous doing anything that would add stress to that tiny tiny rope shaft and those support insulators. Using synthetic lube in the differential seems like it could be a good idea, I can't think of a down side to it.

[mechanickeith]

The torque shaft is much stronger than most people think. The 326 shaft is 3/4" & they very seldom break. They do twist & flex a lot in the manual trans cars, not so much in the automatics. The manual trans shafts do break on occasion from people doing a hard hole shot.