This is a problem that started last fall. I started to get a sound like metal on metal, bad CV joint, drive train etc. Can't feel anything in the car but it is very loud. Stuff that was replaced BEFORE this started included both rear axels after a boot failure, drive shaft center bearing, motor and tranny mounts, rear brakes, new diff fluid. The sound would come and go. After jacking the car up last fall and removing both tires I found the left rear rotor seemed not square with the axel. (tire shop had replaced tires) and when it was put back togeter the noise was gone. Stayed gone for 5 months and 8000 miles till this weekend. On a trip back from Orlando at 75-90 mph it came back. Sounded very bad, would increase with speed, but go away when you let off the throttle. Today I jacked the car up, put it in gear, and the noise was gone after one turn of the wheel. I searched this forum for anything and found some reference to parking brakes causing noise. It was way out of adjustment so I set it back to being set with three clicks. After 50 miles of highway and city, rough and smooth streets still no noise.
So it seems to be fixed, however I am looking for any opinion as to any other cause I may have missed in case it comes back.

Did you replace the drive shafts with OEM driveshafts or aftermarket?

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2005 Audi A4 1.8T CVT -Silver/Black "Siegfried"

1982 300D - Silver/Blue "Ralph" -For Sale:
http://www.peachparts.com/shopforum/showthread.php?p=852260

1989 VW Diesel Jetta Blue/Blue "Bodo" RIP

I had a similar sounding problem on an earlier car. Turned out to be a faulty emergency brake.

The axels were sent out and rebuilt. This was before I found this site and was within 2 months of buying the car. Shop does very good (but not cheap) work and I have them do the suspension, drivetrain work.

I recently had thumpimg noises from my right rear. Turnrd out to be a broke sway bar link ($12 per side) Previousley it had made more subtle sounds but one day gave way. It is a simple DIY job.

This noise came back last night after about 2 miles on the road. Took it to the shop this AM and the mechanic drove and heard it. Said whatever it was would be easy to find as it sounds like something ready to break.
Just got a call and here is what was found... NOTHING!
He removed the rear end cover to check clips, pulled both new axels and they are fine, checked wheel bearings, parking break pads, drive shaft bearings and links, rear end mounts, swaybar links, tires, rotors, the whole 9 yards. Can't find the source and as soon as the car was put on a lift the noise is gone. they drove the car 40 miles in town and highway, 360 turns in the parking lot in both directions both forward and reverse and the noise will not come back. Same thing happend to me last fall. It is a metalic thumping sound from the rear and sounds like the right rear. Mechanic wants it back as soon as it starts up again as this is one he can't figure out. Has been working on these cars for 25 years and has never had something that sounded so bad not be found before. One for the books as he put it. So any more ideas?

Noise is in no way suspension related. It gets faster with speed, louder with more pedal, softer when you let off, in gear or not. It sounds like a CV joint about to fail but no clicking. More like the you better pull over now before it flies apart on you. Mechanic said in mo way would he tell someone to drive the car from the way it sounded this morning, but now after tearing it apart and looking at everything he would drive it no problem. I went over a list of stuff that I found here that could be the problem and all were checked and found to be OK.
And Greg...
I can't sell her now, almost a new car People thought I was nuts when I sold my 95 paid for Dodge to buy a 18 year old car with 200k+ miles on it. I took my time and looked at lots of cars before finding this one. All the records, I'm the 2nd owner, was bought in 83 in Tampa, never been in snow, solid car. I still have things to do like the central locking, oil filter to block leak, and turbo drain seep. Best daily driver I have ever owned as far as comfort goes, and only car that has felt solid enough at 90mph to not worry about anything but a ticket.

I was just kidding,,, that is what I was referring to... everything around this noise will soon be brand new.. but call me first if that noise starts to drive you crazy...( which you would have to be to sell it )... (but at which time you would qualify)...LOL... Greg

Did your mechanic actually take the boots off the axles and check to see that the ball bearings, pockets, etc were ok? I know when I replaced my axles last august, the first set of reuilds were noisy eventhough they did not show visible signs of problems. I took them back to the parts place and exchanged them for another set of rebuilds and they have been quiet so far. This even happened to my brothers 240D, the mechanic put in rebuilt axles and they started making noise 3 months later. He always found some excuse to not replace the axles. You are lucky that you have a mechanic that cares.

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

I will follow this thread, I am very curious about what it is. I got a $600 donor car off ebay in August - for the motor. When I took it for a 10 mile test spin it sounded super, but on the interstate on the way home it developed exactly the sound you descibe - squeaking and thumping that increased frequncy with speed. Since it was a donor, I just let it go and always carried my bike in the back seat in case it ever broke and left me stuck. I drove it till December and never needed my bike. About 1200 miles. It still made the noise when I towed it without the engine and tranny . Keep us posted.

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andy t
'78 300d
'95 volvo 850, wagon
'86 300sdl - engine out, maybe I'll have it rolling by June

whole bunch o' bicycles

I know the mechanic did not remove boots because they do not have the tool to put them back on. With the noise being made he thought that if the shaft was bad he would be able to tell. Also if it was a bad bearing you would think the noise would not go away for months at a time. If it comes back and I take it in he said they will warranty the shafts. The shop is a little higher than most in the area but they do stand behind any work done and I have been very happy with any work they have done.

could be something in the boot that is catching and when you move the driveshaft's joints a lot (like when lifting the car) then the debris could move out of the way.

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2005 Audi A4 1.8T CVT -Silver/Black "Siegfried"

1982 300D - Silver/Blue "Ralph" -For Sale:
http://www.peachparts.com/shopforum/showthread.php?p=852260

1989 VW Diesel Jetta Blue/Blue "Bodo" RIP

Something in a boot would do it. If it comes back I will bring this up.

The noise comes and go, I thought it was a tire problem because it sounded like one (like theres a bubble on your tire) or it might be because of a chopped tire due to bad alighnment. I had MB align my tire (4 Wheel) and the noise was gone. I went on a long drive and it came back. Then its gone, its like a nightmare that keeps on coming back. I am hoping that its just the tires, but I already had my tire rotated couple of times, clicking still come and goes. I though if it was a bearing problem it will be a continuous noise. I will also watch this thread and see what happens..and will keep you posted if I find those gremlins in my rear.

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Edgar
Warminster, PA

It's a CV joint. The things are goofy when they go bad. One day they make no noise and the next day they make noise. Most of the rebuilds use grease as lubricant, which can shift around as the dynamics change. Almost every other rotating part in the drivetrain will make a constant noise except the CV joints. I put in a rebuild a few months back and it has started making noise sometimes, but only when coasting.

My $.02 worth.

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1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold