Got a little crunchy noise from the rear end after driving 60 miles at 70 mph with heavy load. Didn't notice the noise until stopping at a gas station and when backing up it was worse, at low speed. After it sat for a couple hours there was no more noise. And drove 60 miles home without incident. Has a slight shudder at times when turning from a dead stop. Had all bearings and clutch pack for lsd replaced about 35,000 miles ago. Had one other episode like this about 6 months after the rebuild. Shop wouldn't warranty taking it apart because I didn't bring it for gear oil change in 30 days as recommended. At that time we just replaced the gear oil, which was very gritty, and never heard the crunching again until recent. I'm guessing were looking at another expensive repair. Any idea why it only does this when the rear end is hot ?Thanks.Oh just had inspected and new gear oil and friction modifier done , no metal shaving or parts in the pumpkin.

 

Could be tolerances aren't right. Could be a bad bearing.

 

Do you have the limited slip additive in the rear end?

 

Yes , used Mopar gear oil and the additive on the last change a couple weeks ago. Only reason I changed fluids was to have look see if any metal was collecting on the magnet , but it was pretty clean. Does have the slight howl that goes away if coasting then give it a little gas. Clunks a little hard when going from drive to reverse and vice versa.. Yes has the limited slip.

 

I might be tempted to check pinion depth, and backlash.... and test the pattern on the gears. (yeah, now that you have already changed the fluid......) See what things look like. To me, it does sound like a gear setup issue.

 

Have not resolved this noise yet. It only happens when driving 40+ miles at highway speed. After driving that distance and then stopping and putting in reverse there will be a clunk, clunk, clunk. Also does it in forward motion. There will be three cla-clunk, cla-clunk,cla clunks driving slowly about 3 feet. After sitting or cooling down for 20 minutes or so the noise goes away. Had the driveshaft off and u-joints seem to be good. Seems to be heat related as I can drive around town all day without an symptoms. Sound familiar to anybody?

 

Drum or disk rear brakes?

 

Drums on the back. It's a rotational clunk sound that only shows up after driving at highway speeds for a distance of 40 or more miles. If I stop and drive slowly after 40 miles it will make the noise , but I can resume driving another 20- 30 miles at highway speeds without any noise or any other driveabilty issues. Last brake job was a about 6 months ago.

 

Hows the brake pedal feel? Anything change when you hear the noise?

 

Brake pedal feels good. Pedal height is good. There's no jerking or anything like that. The driveshaft does clunk a little hard when shifting from drive to reverse, not quite as hard going from reverse to drive.