300D Heavy Thumping Vibration on Acceleration
 

Hello All,
I have a 1985 300D Euro. When I accelerate from a dead stop the _______ (drive line???) makes a very heavy thumping vibration. It only does it when you accelerate from about 5-15 MPH and only from a dead (or really close to dead) stop. It seems to do this from all dead stop accelerations and is worse in the morning. In the morning if I get up to speed then remove the foot from the accelerator for a second it seems to stop it most times.
I've read through some of the posts and I'm hearing all sorts of things that could be wrong. I think the leading two are the Tranny Mount being bad or the Driveshaft center bushing/bearing.

Thank you for any imput,
Matt

Go over to TECH, I read this morning about a 126 having I think the same issue. Turned out to be a BAD new flex disc, non OEM, that fell apart!

I agree
 

Flex disc or mount issue, Could maybe be center bearing in drive line but you would probably here it more consitantly at higher speeds to.

Sounds like an easy fix.

Get under the car and check the following.

Center bearing rubber diaphram. This is #1 on the hit list in my opinion. It is a rubber membrane that supports the bearing and drive shaft. My SDL did this.

Flex discs. front a rear. If delaminating then replace. Or if shows variations from a solid hard disk plane.

Tranny and engine mounts. It's probably not them but your there so check them.

Dave