I just purchased an 82 300d Turbo. It has 260k miles and still
looks and runs beautifully but for this one thing.

On the drive home I started hearing a regular thunking noise
(kind of like driving on ridged concrete at high speed) coming
from the rear passenger wheel area. It only made this noise
when I put the accelerator down and stopped altogether when
I let my foot off the "gas". It didn't make the noise all the time-
for instance when I test drove it before buying it!

Any thoughts on what this might be. I ruled out things like
brakes and thought it probably had to do with the drive mechanism?

Thanks-
Will

1986 190e 2.3 16v
1982 300TD

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Thanks,
Will

1985 300D- 222k- (bad transmission)
1980 300D- (parts car)
1982 300SD- 242k

I had that on my car right after buying it. Check the axleshaft boots. I found one to be ripped, and the noise would go away when I pulled the axleshaft towards the wheel (it was loose, and no it's not supposed to be ). If the axleshaft will move laterally between the differential and the wheel, and especially if any one of the CV joint boots are cracked, that axleshaft's gone. If I'm right, it's time to change the axleshaft out...not too horrible of a job, and you can get rebuilt axleshafts for $65 apiece at Carquest. I did both just to be safe.

Hope that helps some...good luck!

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2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

thanks Warden-

Further information and ammendments to my previous thoughts
(I have yet to check the axle as suggested).

The noise isn't just during acceleration, although predominantly
so, but can be heard when coasting also. The thunking increases
with my speed.

I will check the axle boots and let you know.

Will

__________________
Thanks,
Will

1985 300D- 222k- (bad transmission)
1980 300D- (parts car)
1982 300SD- 242k

The sound you are describing sounds like a bad wheel bearing to me. To tell which one is the culprit, keep an ear out for the sound to get louder when you're going around a corner. If it gets louder when you're turning left, the bad bearing is on one of the right wheels (and vice versa). If it gets louder when you slow down, the bad bearing is on one of the front wheels (and vice versa). My '84 300TDt has been making a sound like that for about four years, but I don't plan to do anything about it until the noise becomes objectionable.

Best Regards,
Rob

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Robert Fini

'12 ML350 BlueTec, 87k
'06 E320CDI, 270k
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 69k
'97 C36AMG, 313k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)

Really...my experience has been that wheel bearings tend to make more of a roaring noise than a clunking noise...at least, that's what mine did, eh?

The big double race ball bearing type (that are in the rear) can thump -- I had to replace one on my Audi Fox once, what a pain -- had to take it to the machine shop to get the stinkin thing out it was stuck so tight!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

It turned out to be the axle. I will have to rebuild the passenger
side.

__________________
Thanks,
Will

1985 300D- 222k- (bad transmission)
1980 300D- (parts car)
1982 300SD- 242k