Have a "Clunk" that comes from the drive train or rearend. Mechanic has replaced the wheel bearings and said that there is nothing wrong with the car. The "Clunk" does not appear when you "drive hard" only when you drive easy. It is at it worst when your accelerate rapidly and then have to "back out" of the feul rapidly (like when someone pulls out in front of you when you ar accelerating) and then I feel & hear a loud "Clunk" from the rear of the car. It almost sounds like the trans or the rear differential is loose but the car has been like this for 2-3 years. I thought that maybe the differential was going bad and would just replace it when it layed down. Problem is that I won't lay down and I am tired of listening to this "Clunk

robert,
since our earlier exchange today, i was messing with my bowden cable again and taking a couple of turns clockwise smoothed the shifts. it does require some experimentation to get it where you like it both under hard and easy throttle action. meantime were you able to read steve brotherton's write up about mb trannys?


bob

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

Check the vac system for shift control -- leaking lines or bad control valve will cause the upshift to be very harsh when you let up on the pedal, making the tranny thump.

You may also have a bad rear flex disk -- or the front one, for that matter. The thump always sounds from the rear, that is where the stiffest bushings are.

You could also have worn out diff mounts and/or bushings.

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!

I had that "clunking" in the rear-end of my wife's 300DT when coming to a stop and it "magically" disappeared when my mechanic replaced the vacuum control valve (or whatever that valve is on the transmission ???) and plugged another vacuum leak or two.

If it was mechanical, I'd think it would do it at all speeds, but then I'm not a mechanic either.

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Don
'85 500SL (Euro) - 186,000 w/a complete restoration and engine rebuild at 154,000
'95 C280 - 174,000

I second everything psfred said. I bet it's one of those items. Rear diff mounts are easy to check, look at them from the rear, the metal part should be "centered" in the rubber surrounding it. If not, they're bad. The other stuff requires more testing on your part...


Regards,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

The vac signal to the tranny controls shift harshness, and a leak signals for a hard shift when you need a soft one -- BANG.

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!

Also, if you don't have a hard shift on light throttle you'll want to check the rear half-shafts. I haven't ventured into my car yet, it does the same thing, block the car, put the trans in neutral with the engine off, lay down under the rear of the car and grab the actual shaft in between the left or the right cv joints and see if the shaft slides back and forth. If it does, there is your noise. I'm assuming that under certain load conditions that shaft slides back and forth. If it is like any other car, the shaft should have some sort of clip on the end of it inside the joints to keep it from moving back and forth.

My car does it mostly when you go from Park to Reverse, from Reverse to Drive and occasionally on decel.

Hope this helps a bit....