The W126 does not use U-Joints. The driveshaft lays in a straight line between the trans, the center bearing and the differential. It's important to make sure the flex discs are not under any misalignment loads. The engine and trans mounts must be good and not collapsed, the diff and rear suspension mounts must not be collapsed as well as the center bearing.

The older models like the W111 and the Ponton models with the swing axle do ise a U-joint on the aft section of the driveshaft because the diff does move when going over a bump.

I was wrong, there is a U-joint on the front of the rear driveshaft. See your post over on mercedesshop.

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.