DanielD

Ok guys, I've read and reread the many posts referring to the ATF used in the automatic transmission and the lubricant used in the Transaxle with PSD.

There seems to be a wide variety of recommendations.

Simply put the 4 speed automatic transmission uses ATF, synthetic recommended, while the transaxle uses 90W gear oil, GL5 type. The capacity of the transaxle is 4 quarts.

What am I missing here? Why are the recommendations so varied?

dcrasta

You PSD guys are a different breed. I would take a look at these instructions - http://www.928intl.com/repair/psd1.pdf

In any case, when dealing with the Diff, one lesson I learned the hard way. Remove the fill plug first, before removing the drain plug (because you know what happens if you drain the diff and then cannot remove the fill plug? Chaos and agony!)

DanielD

From what I gather, the PSD uses hydraulic brake fluid to engage/disengage the clutch in the transaxle while the transaxle itself is lubricated with 90W gear oil... I don't believe there is any fluid interaction between the drive gears in the transaxle and the PSD system.

dcrasta

ya I think you're right.

I use Valvoline Maxlife in the Trans (~ 8 quarts) : Whatever you use it has to be Dex III/Iv compatible

I have heard good things about Redline 90w gear oil in the rear dif. If you have LSD obviously you should use additive.

Remember.. Pillage then burn [remove fill plug before draining diff..]

the flyin' scotsman

The trans, diff and PSD are 3 seperate systems and require 3 seperate oils:

tranny......ATF
diff...........gear oil
PSD..........brake fluid

All recommendations of types and quantities are in your Owners Manual.

DanielD

Yes, that's what I thought. As for the differential, that's the 90w gear oil, GL5 rating. Now I can move forward on the differential oil change without lingering questions...
Thanks, D

ammonman

I use Mobil 1 75w_90ls in my 1990 diff with no issues.

Mike

DanielD

Mike,
That's what it going in.
D