Bad Clutch Diagnosis Help

[aaroncuyler]

I've been working on a 924 that hasn't been running for years- got it running and now have moved onto the clutch or? torque tube problem. When I compress the clutch I hear nothing, but when I engage into reverse and let the clutch out I hear a horrible grinding. It will go into reverse just fine, all gears seem okay but when I try to engage by letting the clutch out the grinding starts. Previous owner was quite confident that it was the Torque Tube. I've spoken to a few specialist and they have reckoned that it's the clutch- Don't hear any noises unless I try to let the clutch out and move into gear. I've received a quote from a mobile porsche mechanic but want to know if there could be anything else going wrong here? Thanks for any help.

[9FF]

It’s not the torque tube and if it’s grinding when you let out the clutch it means the gear isn’t fully engaged which could be a number of things. (1) Your clutch may not be engaging fully, (2) Your transmission linkage may be incorrectly adjusted, or (3) your transmission is bad.

[aaroncuyler]

Cheers for that. Could it be that the clutch plates are worn out?

[9FF]

Originally Posted by aaroncuyler

Cheers for that. Could it be that the clutch plates are worn out?

Yes it could. There is one clutch plate and if it’s worn out the clutch may not fully disengage the drive which would cause your transmission to grind when changing gears. But there are other reasons that may cause the clutch to not disengage, your clutch may need bleeding which would cause the same problem.

[911tracker85]

if it is the TT you will hear rattling when the transmission is in neutral and the clutch is engaged. when the clutch is engaged it will spin the drive shaft inside the TT, whether the gearbox is in neutral or in a gear.

I am about to replace the TT carrier bearings in mine. rattling but not grinding.

the grinding suggests gearbox issues and a good chance the linkage is out of alignment.

good luck. I just picked up this project. after sitting for a couple years it started and drove across the street to my shop. it is an 87 924S with an auto. the rubber centered flex plate is shot. lots of rattling. was going to pull the engine to use the block to rebuild the motor for my 951, but just found a good engine. once I get the 951 back on the street will put it up on the lift to see how much work it needs other than the flex plate. if not too much will fix and maybe gut to be a DE/autocross car for my partner's sons.

[aaroncuyler]

Thanks for the help here, guys. Great to get some more formal diagnosis. Is there any way to diagnose if it is specifically the gear box? Would you suggest the best action plan is to take the clutch out to examine?
Thanks again

[IdahoDoug]

This is such a basic question that it pains me to think of you having a mechanic involved. You'll likely be told they have to disassemble it to see what's wrong. Then they'll tell you they're not sure but you should replace the clutch and have the transmission rebuilt before putting it back together. In May of 2020 the car will be drivable again and you will have paid out over $9000. Find someone - ANYONE in your circle of friends and associates - who has tinkered with cars and have them tell you what's going on. I can tell from your descriptions you have very little experience here and I'm very afraid you're about to get ripped off. This is such a basic diagnosis (is it the clutch, shifter adjustment or is the trans shot) that you should find someone who can tell you. It would also be wise to tell your location in your signature as likely someone here can help you. If you were here, I'd come over, feel things and in 10 minutes definitively tell you what is likely to be wrong. Don't hire a mechanic at this stage as then "they own you" and will start tearing it apart knowing you're then at their mercy. Nothing against mechanics, just have seen this sooooo many times lately. I'd be happy to talk on the phone as well if you want to PM me for my number.

Doug

[aaroncuyler]

Cheers for that @idahodoug. I am def very new to the Porsche world and am just getting my feet wet here. Diagnosis is probably the hardest part of this whole process. I am in the UK unfortunately (Bristol, England)- but yes would be good if anyone was close by. I'm a bit stuck here as I don't have the experience or space to properly sort! Any other comments or recommendations would be appreciated.

Cheers,
Aaron

[9FF]

Aaron, I’ve heard the Porsche 924 Owners Club in the UK is well supported and should be able to help you. Also look up Paul Woodard at Woolies Workshop.

[Jfrahm]

If you pull the starter and find rubber chunks in the bellhousing, it's the typical blown clutch disc rubber center. When it tears apart there are small tabs that allow some driving but these soon wear out if the car is driven in this state. They can cause a clanking.

New replacement clutch discs have a spring-dampened center.

Other possibilities could be the torque tube couplers or ring and pinion. Easy enough to observe via the access holes.

-Joel.

[aaroncuyler]

Thanks for that guys.

I've already been in touch with Woolies- They are great and super helpful. Bought a bunch of stuff off them too.

Joel- Thanks for the advise. Would that rubber deterioration cause grinding as opposed to clanking?