Potomac-Greg

I want to update folks so that we can all have a better idea of the symptoms of clutch failure.

A couple of weeks ago, after two days on track (actually 1.25 days and of that 0.50 were in the wet) my drivetrain started to show radical lash. Getting on and off the gas showed a huge slack spot; and there was also a lot of gear whine.

Based on wisdom here, it sounded like the rubber puck disk in the clutch plate failed. But the shop (a very well regarded shop for 944 owners) said that the noise was gearbox related. So I was casting about looking for a used transmission, and kind of bummed out that I was still looking at some future clutch failure.

Today the shop calls, very apologetically, and says that they decided to open up my gearbox to see if there might be a simple pinion replacement. The gearbox looked great and didn't have any slop. They went back to the clutch theory and determined that it had, in fact, failed.

So even though I lost a week without the car, at least I will have a strong (Sachs) clutch. And you folks have further confirmation that drivetrain lash (even with gear noise) is a sign of clutch failure.

Rubber Disk RIP @ 72,000 miles.

marky522

I had the exact problems with my car till last week, extreme backlash in the drivetrain and transmission whine. I replaced the clutch and tranny though. Ill have to retest the old transmission before i write it off. Glad you got it figured out.

Mark

Mike C.

There's a phrase you don't here every day....

Marajit

I think I must have gone through a change of dimensions at some point.

Since when did clutch failure become good news?

Potomac-Greg

When it's NOT a transmission failure. They cost about the same to fix, but a clutch failure is inevitable.

Chads996

Good news man...

Here's something for you. My 147K 944 S2 had its original rubber clutch in it when we pulled it off the old motor. And...IT STILL HAD LIFE LEFT!!! Unreal.

C.

jsaindc

I hate to sound naive but what exactly is drivetrain lash? Do you mean like a hesitation?

Potomac-Greg

Lash (as I use it) means that if you are driving at a steady 30 mph and let off the gas, there will be a split second hesitation and then a harsh slamming, and then if you hit the gas again, another hesitation and harsh engagement. It's as if there is slack in the system that needs to be taken up. And that's exactly what it is.

Potomac-Greg

My understanding is that the rubber is good one moment and cracked the next; and it can go bad even though you have a LOT of life left on the clutch friction material. At 72,000 miles, I assume that my clutch still has a lot of friction material left.

Tom R.

FYI my first S2 had 56k on it when the rubber went in 00. the disk had plenty of life on it.

The S2 disk i mailed to marky last week had about 35k miles on it. it was pulled because the tranny was pulled when the bolt for the short shifter snapped.

944Ross

My 84 has a great deal of lash and makes god-awful noise on Coast. The PO claimed it had a clutch job at a respected local shop about 20k miles ago. I would assume that the mechanic went back in with a Porsche OEM part.

How could I tell if it's a rubber center disc? (obviously, without pulling it out) Any chance of seeing thru the inspection hole and seeing it?

Why would the noise come from the tranny if the disc is bad?

Potomac-Greg

I don't know the answer to this. But it does make me think (again!) how useful it might be to have a decent borescope (basically a little camera on a probe) to see things that we cannot see with our eyes (insider spark plug holes, crankcase, etc.)

peanut

two easy tests you can do to confirm it is the clutch cetre rubber at fault.
1. jack rear drive wheel place car in 1st gear rock drive wheel back and forward watch and listen where the slack in the transmission is taken up
2. drive at 40mph in forth gear and see if you can maintain a steady speed without the car lurching forward and back as the slack in the transmission is taken up and let out

The reason the clutch rubbers fail is usually due to deterioration of the rubber over time but slamming the pedal to the floor and sharp de-acceleration will tear it to bits if it doesn't break the CV's or axle shafts first

Potomac-Greg

Hence the failure at the track!

944Ross

My daily drive is 90% at 40 mph and in 4th, it's smooth and quiet as a baby. I'll try the wheel thing.

The records I got with the car show that in '89, the PO paid >$2k for addition of LSD, I have suspected they screwed up the pinion setting when reassembling, or maybe something has come loose?