PeachParts Mercedes-Benz Forum - View Single Post - 300 turbo manual 1700-2000 RPM vibrations

t walgamuth · #47 03-18-2009, 06:00 AM

Quote:

Originally Posted by OM616

Mine is a 84 300D turbo model, BUT the engine that is in it now is out of an SD. Not sure if there is any difference. The shorter manual trans changes the angle of the drive shafts. I want to replace the center bearing. Mine is squishier that I would like, could be letting the shafts move around too much.

I also just got back from 120 mile round trip in my 78 240D. Now that I know what to feel for, it too has a very dampened vibration in the 30-40 MPH range, just like my 300D had until I moved things and the speed changed a bit. The car is very tight in comparison so it dose not rattle and buzz like the 300, but you can feel it come in and out as you drive though the speed range.

I am also not sure if the MB auto trans centerline is a true continuation of the crank shaft centerline as a manual trans is. The GM Turbo350 trans centerline is angled up from the crank. If you look at some model A street rods, you will see many with side pipes that point down towards the road. The detailed builders will have the engine parallel so the pipes are level, but the trans tail shaft will be pointing up. It is under the car so nobody sees it.

If the MB auto is like the GM trans. Then by converting to a manual trans the engine angle would change , which could affect the motor mounts ability to isolate vibrations.

With standard u jounts like is typical on a gm you want some angle to work the joint a bit. On the benz your two main joints are the rubber donut type. You want these to be straight.