Well if anyone is interested i got this issue fixed. About a week ago I was driving to work and my front end locked up solid on me. Piled up the front diff just driving normally through town, the pinion bearing seized up on me and destroyed the pinion ring gear and housing. thankfully it was all covered under warranty because the end result was to the tune of $13,000.00. But now that I have the truck back it doesn't clunk in reverse, so it must have been the pinion moving inside the housing and clunking when I taped the brakes.

 

Wow $13,000! Any idea what caused the pinion to move? Lack of fluid or something? I recently had to buy a new transfer case because all the fluid had leaked out and the chain inside had stretched. When I went from forward to reverse or vice versa I would get a clunk which ended up being that chain slipping teeth.

 

yeah it was pretty bad, The diff was full of fluid and didn't make any noise before it locked up. There pretty sure that the pinion seal had never been changed. but when they tore it apart they noticed that there was virtually no seal left in the housing so they figure some crap got into the bearing and started to destroy it. It got to the point that the inner race welded its self to the pinion then the outer race started to just free spin in the housing instead finally with the heat it locked up and the pinion locked wrecked the teeth on the pinion and the ring gear and the splines on the axle shafts them selfs. They ended up replacing the whole diff housing a full gear set axles and ball joints.

I was surprised that they warrantied the whole thing with the lift kit. They got the truck Thursday morning and had it back to be at 630 Monday night. They did awesome work but there guys cannot do alignments, steering wheel is ed to the left and the truck pulls to the right.... getting that taken care of next week....

 

$13K! Thank goodness for warranties.

 

You have no idea! I had a mini panic attack when they told me that price, I had no idea what I was going todo if they said said it wasn't covered under warranty

 

I empathize. My wallet hurt just at the thought of having to cover a bill of that size.

 

A junkyard axle woulda been put in before $13k came out of my pocket! You know how stout of an axle you could have built for that price....good thing warranty covered it

 

I know this is an old thread, but, I'm having the same symptoms. I have a 2012 2500 6.7 4x4 Megacab. When I'm in reverse, every time I tap on the brake, i hear a clunk. It sounds like its coming from the back. Ive searched online and people have said things like brake pads shifting in the calipers (i just replaced them this weekend and ruled that out), as well as slip yokes that have run dry. This is the first thread I've read that's absolutely terrified me, both financially and at the thought of my truck just binding up on the high way at speed.

Could it be anything else ? Im a bit of a shade tree mechanic but I know this is one job thats probably out of my league. Sorry to revive an old thread but people always say "use the search button", right?

 

I dropped the truck off at the dealership yesterday for an oil change and asked they look into a noise i heard in the driveline. lets see what they say.

 

verdict is in: bad control arm bushings in the front. need new/adjustable control arms. the ones i have on there now are too short and not adjustable (i have a 6" lift and 37's). i wont bump this thread anymore. my apologies.