Drivetrain Rear End Clunk, Burning Rubber Smell, Loud Wine 94 V6 Mustang


New Member
Jan 1, 2014
Odenville, AL
I took the Mustang out on a hundred mile trip, broke down and had to be towed 100 miles home. While I was on the interstate, I heard a loud clunk clunk clunk noise and smelled burning rubber. It proceeded to turn into a deathly wine when I tried to accelerate.

I got of the interstate, and the car continued to clunk even at a snails pace crawl. I though that I might have a sticking caliper, so I removed both of em. Found out that the noise was present when the brakes were removed (vehicle on jackstands).

Also, when I had it up on the stands (rear wheels suspended from the ground), I noticed that the right rear wheel (traction wheel) was not spinning whereas the left rear wheel (driver's side) was - with the car being in drive.

I'm thinking that I need a new rear end, but I'm not certain. Anyone else have this happen? First time I've ever ran into drive line issues.

1995 Mustang V6 3.8 with new headgaskets at 195k.
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How are the axle bearings. Did you grab the axle and try wiggling it ot see if it moved? Any fluid seeping out of the end of the axle tube?

Did you find anything wrong with the brakes?
I wiggled the hubs, thinking that it could've been one of them. I haven't tried wiggling the axle. I'll give it a try shortly.

There wasn't anything wrong with the brakes. No grooved rotors, smooth pads and everything. When I came off the interstate and looked underneath the car, I saw some smoke coming from the differential rear cover.

I've looked up some videos on youtube, and I believe it's within the rear end- comparing the sound of my car to theirs.
Check the seal at the front of the differential. Possible this has failed. I might even consider pulling the diff cover and taking a look. I'd want to see if there is fluid inside. Is a seal has failed (burning rubber smell) then it's possible fluid is, or has leaked out. Wiggle the axles and check to see if the axle bearings have failed, or look for leaking fluid from the end tube seals.

Sorry can't give a more definite reason., but hard to diagnose when the car is not in front of you
I've bought the 98 rear end. It looks to be a non-leaker.

The old rear end is still in the car, but I've made some headway in getting it removed. I believe the front seal failed on it, as there is oil on the rear passenger floor pan. I believe the bearing has also gone bad, as I am able to wiggle the drive shaft a little bit.
Here's the old one:

Nothing noticeably wrong with it, aside from it having zero fluid inside. I believe I could replace the pinion bearing and the seal and call it good. I've got the other rear end in the car now though, so I'm not sure if I'll keep this one or not.