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87 325is "clunk" coming from rear?

Posted by land sea air 
October 01, 2009 01:31PM
Here's what I have so far (had the car less than a week so bear with me)
Does it most often shifting to second or sometimes third, seems to happen less if I'm quick and smooth with the clutch. U-joint on drive shaft seems to be fine, less than a mm of play if any at all. haven't had a chance to inspect the guibo yet or see if it has the secondary balancing drum, but the noise seems further towards the rear. Going to look at the trans mounts again this weekend but again sounds more rearwards than this, will be replacing them anyways soon. I don't think it's suspension related as I can shift the weight of the car without it happening. Axles seem to have a small amount of in/out play and a small amount of diff play as well, but the noise isn't constant so I'm not sure if this could be the culprit. Any help would be much appreciated!
October 01, 2009 10:05PM
It's probably the center bearing on the driveshaft. Tyler posted a nice video of his in the driveshaft thread that you've probably read by now. All the rubber was gone from the area between the bearing and the housing that holds it in the video. Yours is probably in about the same shape. Mine was like that too when I first got my car. I replaced the center bearing before I ever drove the car, so I didn't get a chance to hear what a bad one sounds like while driving. One thing to keep in mind is that I had to replace my driveshaft not too long after I replaced that bearing, which cost about $50.00. If it is your center bearing, and you have any doubt about the driveshaft, it might be worth it to just apply the cost of the bearing to the new shaft. You get a new center bearing with the new driveshaft and if you have to return a core for the shaft you buy, your nice new bearing is going to have to go with it.

You sure got a nice car. Those pictures in the other thread were great.

John
October 02, 2009 07:07AM
Thanks! I'll pull the exhaust next weekend and see what I can find, I know it makes sense to replace the whole thing since the DS has to come off but I will probably have to wait for now sad smiley
October 03, 2009 04:42PM
In out play on the axles is normal. Movement is required for the suspension to be able to travel up and down since the diff is strapped to the frame.
I could be wrong, but a bad center bearing or drum won't make noise, and they certainly won't make a clunking noise. They WILL cause vibration though. I would place a twenty on the clunking being your U joint. When testing it, you really have to yank it hard. On mine the metal started to tear, so it would get " stuck" in a position, before applying a hard shiftthat would break it loose and then CLUNK!

It could also be the diff I suppose. But I reall don't know enough about the diff and its potential problems to say.

Do you get vibration in the car at freeway speeds?

(sorry about any grammar or spelling. Written on my iPod)

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1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles

October 03, 2009 04:48PM
I haven't noticed any unusual vibration at speeds, I will however check the DS again.
November 16, 2009 01:00PM
Upper shock absorber mounts (accessable through the trunk) fail frequently and can cause an occasional "clunk" in the rear. The mount is rubber and simply breaks apart.
November 16, 2009 01:07PM
Actually I just checked this yesterday while I had the trunk apart. They look fine as far as I can tell.
rkj
November 16, 2009 10:52PM
The shock bushings in the rear are more of a, hitting a bump in the road thing, you'll get it backing out of the driveway.

Take a good look on that shaft, like Tyler sez, you gots to apply real pressure sometimes on those U joints.

Do you have LSD?, they tend to be quite noisy.

Rick
November 17, 2009 01:07AM
Quote
rkj
Take a good look on that shaft, like Tyler sez

Hi, I'm Tyler. I realized I haven't signed my name in this thread, so a noobie may not know my name :-)

-----------------------------------------------------------------------------------
1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles

November 17, 2009 08:02AM
I do have LSD but I was under the impression that the only time you should hear it is when you're spinning the wheels. I haven't had a chance to go back under the car yet since I've been spending all my time enjoying it. Right now I'm planning on replacing the whole drive shaft since that includes the Guibo and CSB anyways. Also I know I promised pictures in the other thread and once I get a new camera I shall oblige!
rkj
November 18, 2009 03:18PM
Quote
land sea air
I do have LSD but I was under the impression that the only time you should hear it is when you're spinning the wheels. I haven't had a chance to go back under the car yet since I've been spending all my time enjoying it. Right now I'm planning on replacing the whole drive shaft since that includes the Guibo and CSB anyways. Also I know I promised pictures in the other thread and once I get a new camera I shall oblige!

That's a smart way to go, I did mine last year (plus a new exhaust) and the car is fantastic smiling bouncing smiley

The LSD's are noisy and usually have a fair amounts of play in a number of places- They go forever though smiling smiley

Rick
January 12, 2010 01:32AM
Quote
land sea air
I do have LSD but I was under the impression that the only time you should hear it is when you're spinning the wheels. I haven't had a chance to go back under the car yet since I've been spending all my time enjoying it. Right now I'm planning on replacing the whole drive shaft since that includes the Guibo and CSB anyways. Also I know I promised pictures in the other thread and once I get a new camera I shall oblige!

Actually, I don't believe you should ever here it in the e30. If I'm not mistaken, it is a clutch type LSD, and you shouldn't ever hear it.

You should also check your rear sub-frame mounts. When they are bad they will cause a clunk on acceleration. Also, I noticed your mileage, and they probably should have been replaced at least once by now, but many people put this job off.
rkj
January 12, 2010 11:24PM
Quote
Andy 90 325i
Quote
land sea air
I do have LSD but I was under the impression that the only time you should hear it is when you're spinning the wheels. I haven't had a chance to go back under the car yet since I've been spending all my time enjoying it. Right now I'm planning on replacing the whole drive shaft since that includes the Guibo and CSB anyways. Also I know I promised pictures in the other thread and once I get a new camera I shall oblige!

Actually, I don't believe you should ever here it in the e30. If I'm not mistaken, it is a clutch type LSD, and you shouldn't ever hear it.

You should also check your rear sub-frame mounts. When they are bad they will cause a clunk on acceleration. Also, I noticed your mileage, and they probably should have been replaced at least once by now, but many people put this job off.

You'll never hear anything when you're spinning the wheels, but put it in gear (with the motor off) and go under the car in the back and rock the car back and forth and tell me what you hear, and where...

Rick
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