I drove about 600 miles yesterday and for the first time had a full trunk, fuel tank and 3 passengers. I started to notice a dull vibration as I would press the accelerator pedal slightly to go up some long inclines. Also as I would decelerate there was a sound almost like a rubbing sound coming from the back.
I am obviously thinking drive line ( rubber coupling ) I will crawl under her later and see whats up she made it home fine with an average speed of 75 mph ( not my normal speed but just to keep up with traffic. Thoughts
Alan

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92 500E Silver 66k
82 Porsche 911SC 84K
68 Cadillac ( Gone Now )
03 Suburban Z71 200K
85 300SD 217k From Original Owner ( Dad )

As indicated above the first places to start looking; Drive Shaft Support and Flex Discs should be inspected.
When my similar Drive Shaft Support Bearing went bad on another Vehicle; I had jacked the Rear Wheels off of the Ground and put it into gear. The Drive Shaft Support bounced up and down as the Drive Shaft Rotated.

When I got the Support loose you could feel that the Bearing was clearly bad.

Differential Oil level?
Rear Wheel Bearing or Axle problems will be harder to pin point.

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84 300D, 82 Volvo 244Gl Diesel

Agreed, a visual check for the flex disc's and try to rotate the drive shaft to see any play in the center bearing.

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83 SD

84 CD

I had a bad vibration soon after I got the car back on the road a few years ago. It turned out to be the rubber bushing on the center bearing support was shot.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012