924Board.org

ddire · Joined: 14 Nov 2005 Posts: 17

Just got a 1980 924 (euro) and it's great fun - i do have a clunk noise (from the back end) just once each time put the pedal down - most noticable in the higher gears. Just wondering if i can get some clue at what to looking at - am thinking CV's as the car has alot of history and no mention of them being touched - the gearbox was replaced 10k ml ago.

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Think simple solutions first...

How are the rear shocks and the exhaust system? If the shocks are worn/bad, the car could be squatting on accellleration with the body or cv axles banging on the exhaust system.

The exhaust system could also be banging somewhere due to poor fit, or sagging due to missing hanger/s, or rust damage.

Cv axles click when worn or in need or service. Wheel bearings grind.

ddire · Joined: 14 Nov 2005 Posts: 17

Well its not a grind or the click you get when a worn cv goes round a corner - basicly sounds a like it was hit with a large hammer - I checked the exhaust / suspension today and couldn't see anything wrong. I think it's freeplay in the drivetrain somewhere just need to narrow it down. thanks for you help gohim

ddire · Joined: 14 Nov 2005 Posts: 17

Ok I have done a lot of searching on this and a bit more testing. The "clunk" comes with both putting the foot down and letting off - again most noticable in 3rd, 4th 5th. Other wise the transmition & clutch is great - no whineing noise and all gears select smoothly. From what I have seen on the site this could be:

- bad transmition mounts (most likely as i know it has been changed)
- Damaged clutch center
- worn rear shocks / bushings

Any others?

How to check the transmition mounts?
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1980 924 lux Ireland

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

I have similar symptom in my car, but I always put it down to final drive wear.
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

ddire · Joined: 14 Nov 2005 Posts: 17

Had a better look at the back end today. Checked the play in the drivetrain by jacking it up and seeing how far i could move the wheels round while in all the gears before chatching. Ranged from 1/2" in 1st to 1 and 1/2 " in 5th (at the edge if the rim). Transmition mounts seem fine. Did notice quite a bit of the play was from both the cv's at the transmision end of the drive shaft. Think is will look into replacing them first. Hope this is what is causing the backlash.
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1980 924 lux Ireland