I recently purchased a 1983 300 SD Turbo Diesel, this car is overall in very good shape, and I love to drive it. However the last few days at speeds between 50-65 mph it will all of a sudden start shaking and vibrating violently with the only cure to be is slowing down to about 40 then it will go away. The whole car seems to shake including the steering wheel. I have tried putting the trans in nuetral, turn off the A/C (maybe stuck compresser), but it still does it. I looked underneath and everything seems tight, including wheel lugs. There is grease in the front bearings. This baffles me as it is intermittant and seems to occur about every 50 freeway miles or so. I do have a few other questions about Mercedes diesels, as this is my first one, but this one is of my utmost concern. I hope that somebody can point me in the right direction as I do not want to start replacing items that "might" fix the casue. I am sure that it could use new eng / trans mounts considering the age, but my experience is that those would not casue an issue as this. Please help!!!

 

I just jacked up the car...I have seen many jacks in my time, but this one is quite interesting..anyways...There is some minor play in the front curb side axle when I move the tire / wheel assy back and forth by hand with a slight squeaking sound when I rotate it front to back. I could not see any play in suspension components. Could this possibly be a wheel bearing? I have read up on ball joint replacement..not fun...am thinking should have stuck to Chevy's. I do consider myself very mechanically inclined but haven't come across this one. After all we can only define ourselves by our experiences.

 

Jaycodyp: Have you checked for play in the universal joints and main bearing in your drive shaft - from the tranny and before the rear axle? Had this problem with my Chevy at one point -vibration at @50-55mph consistent- and replacing the u-joints and bearings corrected it.

 

Okay...Replaced upper joint on pass side, balanced all 4 tires. Seemed to do the trick, but.... Went about 150 miles but shook once hard, then stopped as I slowed to about 40 mph. Got back up to spped and then it disappeared. Gonna replace the lower one and see if that cures it. Seems to be a nightmare!! The alignment is about 95% perfect now, as it used to pull to the left quite a bit. I can still move the tire / wheel assy front to rear slightly..as before it was more pronounced. It then makes a squeaking noise when doing this. Can anybody verify that this is the lower joint as I hate to throw parts at a problem. I will check out the driveline once I coerse my neighbor into letting me use his ramps... Thanks for pointing me in the right direction. I plan to drive this car from Ca. to Ar. and back later next month and want everything to be in mech. sound condition when I do.