Mechanics

THUMPING NOISE FROM REAR OF CAR

1999 BMW 328

Tires and Wheels problem
1999 BMW 328 6 cyl Two Wheel Drive Automatic 65K miles

My car just started making a horrible thumping noise and runs almost as if it has a flat rear tire (I checked, it doesn't). Additionally if I go down hill both the thumping sound and rough feeling increase, going 40 MPH or over also leads to an increase in the sound and feeling. The sound is almost as if there were someone in the trunk banging to get out (I checked, there isn't anyone in the trunk). I have not run over anything, or gotten into any accidents or evendriven like a crazy person, this sort of happened yesterday out of the blue. Can you help me?
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Larah8668
January 16, 2009.




Rear wheel drive? Do you think it could be your rear axle? Hard to diagnos a noice. 65K does sound too young for an axel to go out. Do you have any more info, see if your lug nots are tight, how is your tire condition?

Tiny
Kevin12881
Jan 16, 2009.
Thoase are darn fine questions! I had new tires and wheels put on just about 6 months ago and nothing was said at that time about anything looking worn or problematic. I have not inspected the lugs or anything else at this piint. My plan was to ask you all to get a rough idea and then move forward with who to take it to.

Tiny
Larah8668
Jan 16, 2009.
Well it could just be your rear axel (differential) I have never had one go out, but the noises seem to acompany all that I would expect from such a problem. Speed would increase the noice as well as coasting down hill, if it is geared low. You are supposed to change the lube in our rear differential every two years, I have never done so and once again have never had one go out. From your user name I do not think you are fixing this yourself, I do not mean to be judgemental. So here is what I suggest. Any car shop should diagnost your problem for free, when you are positive what is wrong just call around and see who is the cheapest. You could call around and see who would replace it cheaper before even taking it in, and they will verify if it is or is not the issue. Could get pricey.

Tiny
Kevin12881
Jan 16, 2009.
Yes you are correct I will not be repairing it myself! Just had it towed to the local Les Schwab tire center for them to take a look at. I was on my way there when the rear end shook and made a horrible sound, so I had it towed from there. You were right about the lugs, there was only one left, on the drivers side rear. They were all there this morning. The tow truck driver said both rear tires were loose, i.E, the lugs were only finger tight. NOT good!

Tiny
Larah8668
Jan 16, 2009.
You are luckey they did not come off while driving. I am glad you are ok, but sorry about the towing bill, and more that may come. I beleive that the lugs were the issue the whole time. If the tire were put on 6 months ago and you have not driven too much, I would have a nice little talk to the people who installed the new tires. Make sure that the wobbling tires did not cause additional damage.

Tiny
Kevin12881
Jan 16, 2009.
P.S. I am not sure if your lugs are studded, meaning bults and not nuts. I would really make sure that the mounting apparatuses associated with mounting the tire, and the braking components, were not damaged. You should have four wheel disc brakes.

Tiny
Kevin12881
Jan 16, 2009.
You were right! It was the lugs the whole time. I am so lucky! It ended up not costing me anything and everything has been checked out and it's running great!
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Tiny
Larah8668
Jan 20, 2009.
We are glad you are ok. And thank you for letting us know the outcome. If ever you need help again, we are here

Tiny
Kevin12881
Jan 20, 2009.

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