Porsche Enthusiasts Club Forum

Taken my 928 for its first decent run in a few weeks. The auto transmission is OK when cold or warm but when hot it upshifts at much higher revs and will not shift from 3rd to 4th at all; even at 4500rpm plus

I have checked the fluid level when hot and it seems very high. I have removed some fluid (about 750ml ) and it now sits between the max and minimum lines on the tank. I will give the car a run later and check the fluid level again.

Most problems seem to be due to low fluid levels; what problems will a high level cause (if indeed it was high)

Some transmissions tends to ''foam''. when overfilled., that air in the oil prevents the trans from operating properly. It can also blow the oil seals in the trans.
When was the last time you drained the trans and refilled with fresh ATF, if the ATF is a sort of brown colour and smells ?, and not cherry red it probably needs changing and to the correct level.
Thats what I,d try first, don,t know if the trans on 928 autos has a screen filter fitted ( mines a manual)
Sorry could,nt be more help

Ken

Hi Steve

Umm I think you just made the problem worse lol....

OK...testing the level... HOW EXACTLY did you do it as its impossible to overfill a 928 tranny as any excess is forced out of that fill bottle...

Soooo if you removed some, you made it worse....

Bad upshifts are almost always caused by LACK of fluid (too LITTLE not too much)

The way you test the fluid level is as follows....

GET engine and tranny fully warm (drive for at least 20 mins)

then get car in air ready to look at level....

THEN put tranny in EVERY GEAR and hold it in that gear for at least 10 seconds.... then the next gear for 10 seconds and so on....

When that is all done check the fluid level....

All the best Brett

Yes they do. I think they're Merc' parts, that's where I got mine.

Admission of stupidity time I checked it when hot but NOT with engine running consequently fluid level looked high. When I checked it correctly the fluid level was very low so I have put it back in (I saved the fluid as it was clean). I am now short of fluid but only slightly and I think this is due to spillage during the taking out/ putting in debark-le but obviously can't be certain

I will get more fluid and try it again in a few days and feedback but I'm not convinced its a fluid level issue.

To cap off a really great night I drove the car with he handbrake half on for a few miles (don't normally use it) and then bashed my chin spoiler on a kerb

Going to watch TV and stuff my face with chocolate

Thanks for the advice