Avec

My wife mentioned that there was a vibration in her ML-320. I took it for a test drive and realized that the vibration was the drive shaft flopping around. The front rubber bushing or whatever it is let loose about a mile from home, making it much easier to spot.

What exactly is that part called? It looks like it centers the rear drive shaft into the rear of the transfer case. Is it a matter of pulling apart the U-joint and replacing, or is there more to it?

Thanks in advance.

Avec

To close the post, it was the drive shaft center support - failed completely and came out in 4 parts. It is a b1tch to get out of there, but very doable. A helpful hint for anyone going to do this job. Have a propane torch ready to go. Every bolt turned in this repair has factor applied loc-tite and it is really strong stuff.

Steps.
Remove small bolts from u-joint at front end of main drive shaft. (Use the torch on these, and all bolts, with one exception noted later) Using a long screw driver pry apart u-joint, then let return to hold in place while rear is removed. Remove 4 16mm bolts holding shaft to diff, set drive shaft aside.

I found it easier to remove the yolk from the rear of the short shaft going through the center support. You will probably need a puller, but a hammer and long rod will also work.

Remove the allen head bolts holding short shaft to transfer case output (6 of them, no need for heat on these) You can then snake the short shaft out of the way.

The two bolts holding the support to the frame cross member are 16mm. Use the propane liberally up through the access holes in the cross member. Without the heat, they are almost impossible to remove.

For installing the center support, I threaded the bolts most of the way back in, then reinstalled the short shaft before tightening the bolts.

mihir_d

Wow...nothing on this trucks is perfect....

Thanks for posting...all I knew about the drive shafts was that the whole drive shaft assembly is pretty complicated. First time ever heard of someone DIYed a drive shaft problem..

Avec

I don't know what the cost of the repair would have been, but it would have taken a flat bed just to get it there. The support let go before I knew what it was, but fortunately, I was on a test drive to figure it out, so I was only about 1 mile from home. Even idling down the road the thing banged like holy hell. I am guessing 2-3 hours labor at the shop. It took me longer, but I did not realize to use heat until well into it. Had I brought out the propane torch earlier, it would have been much, much less hassle.