hello
on my '81 300 SD TD I have had a bad vibration (much more than a harmonic, i can feel it in the car seat) that occurs at about 25 and 35 mph. Pressing the accelerator makes the vibration (more like a fast thumping) more pronounced. When up on a rack, vehicle running and in gear, i could see the driveline moving around behind the front flex plate. By moving around, i mean i put my finger "riding" on the shaft as it spins, and my finger goes back and forth; pronounced out-of-round.
I dropped the exhaust and shield, some rubber pieces fell out, must be the "rubber dust shield" talked about in this article
How to replace the center bearing, support, and flex discs W126 3.0
in moving the driveline around, I think the bearing is good, the rubber is still good around the bearing, i can move the driveline around with force and the rubber gives. there is slight play in the two shafts at the u-joint (twisting each different directions it has a very small amount of play) is that bad?
the big "flag" to me, is the metal collar holding the two drivelines together at the splines just in front of the carrier bearing, is totally loose; it spun with a flick of a finger.
at this point:
do i need to replace the dust-shield (maybe comes in a bearing set?)
do i need to replace the u-joint?
do i need to get the driveline balanced?
all the above?
or maybe i need to tighten the "collar" and test drive it???
thanks everyone
Guy