The new trans mount is in but alas the vibration remains.
I am more convinced than before that it is somewhere in the rear end of the car.
We checked the lubricant in the axle cans and it is still there and fluid.
The diff lube is fresh,
Minimal rotary play in the driveshaft.
Wheel bearings are ok but not perfect. A little movement in the right rear wheel but not excessive.
flex discs ok
new center carrier and bearing.
Any other input here this is really frustrating

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

If you can "feel" movement on the right rear wheel I think you might want to measure it.

It should be 0.04-0.06 mm

See

http://www.peachparts.com/Wikka/W123RearWheelBearings

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

A possibility is the driveshaft center U-joint is seized & binding. Unfortunately, those are staked in place and not normally replaceable without buying a new shaft-section.
However, there are driveshaft shops that can cut & weld in a new driveshaft end with a replaceable/greasable U-joint.

Happy Motoring, Mark

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DrDKW

DS ujoint is a little "notchy" but not seized or clunking

__________________
1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily