Replacing diff carrier bush in w108

[ADow]

I have persistent clunk in the rear diff region. It's almost certainly the diff carrier bush (not sure of correct name for this part) - Part 322 of the attached diagram - has anyone had any experience with replacing this part? As is involves removing the back axle and dismantling the diff, is there anything else that I should consider checking/replacing.

[psfred]

Replace the upper mount for the diff carrier first, along with the rubber bushings on the control arms (both ends) before condeming the diff bushing, as all of them are easier than the bush.

I've not done one, I'm hoping mine is in good enough shape I won't have to.

A bad upper mount causes serious clunking noises radiating from the front of the trunk, and bad control arm bushings will cause, along with the bad diff carrier mount, rear axle steer, excessive "pitching", and overall rear suspension harshness.

I need to get all that done after I do the engine swap....

Peter

[ADow]

Originally Posted by psfred

Replace the upper mount for the diff carrier first, along with the rubber bushings on the control arms (both ends) before condeming the diff bushing, as all of them are easier than the bush.

I've not done one, I'm hoping mine is in good enough shape I won't have to.

A bad upper mount causes serious clunking noises radiating from the front of the trunk, and bad control arm bushings will cause, along with the bad diff carrier mount, rear axle steer, excessive "pitching", and overall rear suspension harshness.

Peter the control arm bushes are ok, but I'm not sure about the upper diff carrier mount. How do do you test it?
Alastair

[JMela]

If you're getting a tunk-tunk sound from the rear when going over a bump, it's a good bet the mount (#353 on your diagram) is due to be replaced. Also, if it's ten years old or so, might as well swap it out. They get compacted and tear over time.

Another bushing to be (eventually) replaced is the the control arm/ axle bushings (#335).

[Arthur Dalton]

The trunk mount is easy to check .. take the cover off [ in the trunk-2 screws] and you will see a big, flat washer on top of the mount ,, this washer should be at least 1/4" abuve the frame of the mount . If it is resting on the mount frame, it is shot.
This can be confirmed by placing a floor jack under the diff and watching the mount when jacking the diff. As it raises off the mount , you will see the rubber mount suspension insides and they will be all ripped and cracked.
The noise that is heard from a bad one is the washer rubbing on the frame, whereas it should not touch any part except the rubber in the mount.
On the lower hanger , it can be changed in the car , but the pinion flange has to come off.. this is a little technical cuz the pinion nut has to be indexed or you can run into bearing load problems
I have wriiten a procedure for this repair ,if needed.
This hanger usually suffers from oil contamination/distruction to the interior
rubber due to long time pinion seal leaking/seepage.. if you have that condition, you prob have a bad lower hanger mount...
This can also be seen with a trained eye. If one looks at the pivot pin end bolt and the anger mount , you will be looking for them to be centered with each other . If the pivot pin bolt looks off-center from the hanger circumference, the rubber interior is shot or well on it's way. Best to look at this with wheels/axles level,[ loaded suspension].. not on a lift with axles hanging

[ADow]

Many thanks gentlemen - this has been very helpful.
Alastair