Open Road

Hi Folks

Craig here from Cape Town. I have had four 928s and never a problem. I have a 1989 S4 with the diff lock. It is an auto and the diff light is across the instrument panel. The oils and the filter have been replaced and before that, she was shifting fine. However, in reverse, she would clunk. Now that the oil and filter have been replaced, she will not reverse freely. I have to give her gas to go backwards and there is quite a bit of resistance.

In Drive she moves off freely but the upshiftifting is near impossible. She runs into the red and I have to ease off before the car will go up a gear and she will not go into final drive.

I checked the solinoid in the spare wheel well and it was dead so I replaced it and then the 30A fuse blew and keeps blowing.

I am lost so if anyone out there can perhaps help, I will be grateful.

Craig

Sounds like the PSD hydraulic system is dead and the PSD slave cylinder is also locking up or the clutch packs have disintegrated. Whatever the failure mode(s) your PSD system is in serious distress.

Research the PSD system. Rebuilding it can be a DIY process, but it’s best left to a specialist IMO.

Worf,
Did ROW 89s have PSD? IIRC, PSD was a 1990 innovation.

Stepson wrote: ↑Wed Jan 03, 2024 5:43 pm Worf,
Did ROW 89s have PSD? IIRC, PSD was a 1990 innovation.

Yes, PSD was an option RoW for MY’89. Standard everywhere as of ‘90.

If he’s got a 30A fuse in the spare tire well (as described above) then he’s got PSD.

Check your wiring diagrams.

Under the ‘right’ conditions a USA/CAN ‘89 instrument cluster will issue a PSD off warning.

Good to know.

Fred with the blue GTS on the OS has also experienced this issue,
his slave leaked the fluid into the diff and took out the clutch packs.
he has a thread started .

https://rennlist.com/forums/928-forum/1 ... ng-up.html