Okay here goes. I understand the prospect of diagnosing this with out hearing it is slim to none but I am at my wits end. I have been chasing a grinding or rattleing but it is a sound I am sure is rotating rather than vibrating. Almost a clatter. Are you guys laughing yet? It seems to come from the drivers side by the rear door, how ever at times almost under the floor board. I cant feel it only hear it. My first thought was front drive shaft as it had alot of slop (replaced) Next was a failing transfer case (replaced) Lastly I replaced the rear end. The noise persits. Its is perodic only at speeds around 55-65 not constant. If I increase speed to 75 or so noise disappers. If I shift to nuetral at speed noise persists, so load dosent seem to effect it. When parked if I rev engine and hold at driving RPM there is no noise. Also should note the catalytic convertor is new and the exaust is good, front bearings recently replaced. I am sure its not a heat shield. Any help or ideas from you guys would be awesome.

Dave.

 

when you replace the front drive shaft did you replace the u-joints? other then that the best thing that i could suggest to do would be to just crawl under neath it and just start checking for anything that could to loose, vibrating, or rubbing on the drive shafts. do you have any vibration in the steering or the drive train that you can feel while driving?

 

How are the universals on the rear drive shaft? They could be worn or dried out, are they greasable?