924Board.org

[epsylon]

This morning on the way to work my 931 decided to break. I am not sure what broke though. It is not the motor and not the clutch. I think it is transmission or something there of. In gear or out of gear the car makes a knock coming from the rear. The knock is related to the RMPs. As I costed to a stop the knock slowed and then final stop when the car did. I turned off the car and pushed it into a parking lot and it was knocking while i was pushing it. It is coming from the transmission or right around there. Any ideas. I can shift it into every gear and it will drive but it is super loud and it sounds like something is hitting metal so i had it towed.
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'82 931
'78 928
Howell Henderson
South Padre Island

[924RACR]

Did you look under there? Broken CV joint?
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Smoothie]

I'm thinking something similar. Start with checking the stuff that's easy to check - crawl under and give the cv joints a wiggle and inspect the bolts, then jack it up and give the wheels a wiggle - check the lugnuts and the large axle nut.

You could also jack up one rear wheel at a time (,but don't do this if you have a limited-slip diff) - start the engine and ease out the clutch, letting one wheel spin to see if you get the noise, then do the same to the other side. This might help you to narrow down where the problem is.

If you get the same noise from both sides, it's probably a transmission or driveshaft problem, then you could put it in neutral, start the engine and let the clutch out (and apply the e-brake). That'll spin the driveshaft along with part of the transmission, so if the noise is there with that, you can suspect the driveshaft bearings (and possibly the tranny). Then to isolate the rest of the transmission, you could find a deserted road, drive along at 25, 35 mph (whatever), put the transmission in neutral, and while coasting - shut off the engine and let out the clutch. That'll stop the driveshaft and whatever parts of the transmission that were moving in the previous test, leaving the rest of the transmission, the differential, (and the rear wheels, cv's, axles, which were previously checked), spinning.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[welder]

BINGO....I'll bet a lose wheel nut or bad CV joints.
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I have a 78 n\a currently under restoration.

[CMXXXI]

Start with REAL simple... are you sure all your lug nuts are tight? The sound a loose wheel makes is very similar to what a bad CV sounds like.
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'79 Eurospec 931

[Smoothie]

Yeah back when I was more of a novice and my brother was even more of a novice, I popped over to help him with his old Volvo. It was a rythmic clunking from the rear and his diagnosis was a bad U-joint on the driveshaft. He got the parts and we commenced with the disassemblage (with some difficulty I might add)...finally got the driveshaft off and brought it down to the basement for surgery, but we kept wondering how replacing the U-joint was going to make a bit of difference because there didn't seem to be any play in it. Anyway, we went ahead with it...too many hours later in the cold it was finished and reinstalled and I found myself with a free moment so I went to a rear wheel and pushed the car sideways and guess what.. Loose friggin' lugnuts. He just had some new tires put on at Kmart earlier in the day and they didn't tighten the lugnuts.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox