Yesterday, I figured I'd flush the Limited Slip Differential and change out the manual transmission fluid while I was at it.
You can you imagine my surprise when the LSD parts seemed to be gone from under the left, rear wheel! (see photo).
My questions are:
1. Has anyone ever seen these removed before and is it ok?
2. Is it possible my '90 GT didn't come with it from the factory (my instrument cluster has recorded LSD errors before, and I thought all GT cars had it)
3. Unrelated, but any trick to get the bottom fill plug out with the exhaust in the way? There isn't enough clearance to get my allen socket and wrench in there.

Missing LSD?


Inner rear, left wheel where I think the LSD would normally be located.

Thanks,
Dustin

 

That appears to be forward of the rear wheel. The pump is aft of the wheel.

 

Oh god. Hah. I'll check tonight. Thanks Mark!

 

Correct!

 

Ok, well I went to flush the PSD the other day and went to find it was empty of fluid. I replaced it with Castrol Dot 4 and followed the procedure at http://www.928intl.com/repair/psd1.pdf.
I didn't do the last part on the PSD slave cylinder b/c it was hard to get up there, but figured it would be ok. Anyway, when I went to run the car the ABS light and Differential Lights were both on now.
Do you think it was because I didn't do section "VI Flush the PSD lock slave cylinder and pressure line" or could it be I messed something else up while doing the main section of the procedure?

Thanks,
Dustin

 

Did the ABS pump run when you turned on the key while bleeding it?

Did the pump build up pressure and shut off?

 

Yes, it ran when I did that. After I was finished bleeding the system, I reconnected the pump and it ran again for a few seconds and then shut off as I expected based on step 21. It's possible I did something wrong during that step but it seemed pretty straight forward.


21. Reconnect the electrical connector to the hydraulic pump to charge the pressure accumulator with
fresh hydraulic fluid.

 

Changing diff fluid requires moving exhaust out of the way. Remove the fill plug first, if it doesn't come out you'll have a much larger issue after taking out the drain plug ;-)

 

/\ /\ THIS is VERY important!

 

Does the warning come on with just the key turned on, or do you have to drive the car for the warning to appear?

 

Did you forget to connect the 2-pin lead for the lock solenoid?

Is the 30 amp fuse for the pump blown?

On the other hand if you are getting both ABS and PSD off messages, then the problem is on the ABS-side.

 

thanks for the replies. I haven't been able to get back under and troubleshoot. Unfortunately I planned on taking this to the Porsche Parade in Spokane next week but with a few lingering problems looks like it will have to stay home.

 

Given that the slave cylinder is "dead ended" I would suggest that flushing it is is a critical part of the procedure as the fluid there was in relatively poor condition compared to the rest of the system when I flushed mine not that long ago [I have a thread on this]. All you need to flush the slave is a 7mm ring spanner - hang that on the nipple and then connect the drain tubing. I thought it would be difficult but in fact it was the easiest part of the procedure- just make sure you wear eye protection at all stages of the flush.

In your case given you had no fluid in there to start with I have no idea what the consequences may be. At the very least I would be inspecting your system to see if, now it is filled, whether there are signs of leakage anywhere. You will only get the air out by flushing it - not that it will have much volume when at working pressure!

 

I have to drive the car about 5 minutes before the warning messages comes on. Both come on at the same time. Rear Differential off and Anti-Lock brakes.

Thanks

 

Some good info here.
https://rennlist.com/forums/928-foru...procedure.html