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Mustang rear axle

Has anyone with a "01 Mustang had a rear axle break?

This is a great forum, but you will be fishing in much better waters in a Mustang forum. There must be dozens of them. Be sure to tell them, specifically, what kind of '01 Mustang you have, V6, GT, Cobra.

You might provide some info about exactly where the axle broke. The answer could depend on that.

Cracked housing, lack of oil, leaking oil seal, stripped splines on an axle, shelled out spider gears or pinion gear, any accident history, etc.?

Any history of rear axle lubrication services being performed, or partially performed. (as in draining gear lube and forgetting to replace it)

Don’t know any particulars. The reason I am interested is that my daughter was driving her mustang, heard a clunk, lost all control, hit an embankment, and flipped over. She was miraculously able to get out, airbags undeployed, and only minor bruising, etc. The car is totaled according to insurance, but she was told that the rear axle was broken. Mostly wondering if this is something that has happened before. Thanks!

Without seeing the damage it would be impossible to even make a guess as there are a number of things that can go wrong with a rear axle that could lead to something like this.

Assuming both rear wheels stayed in place and one or the other did not separate from the car, a guess (wild one at that) would be that something related to a trailing arm broke, etc.

If one of the rear wheels separated from the axle housing and went a different direction than the car was traveling then I would say there was an abnormality in the differential (possibly a C-clip coming off an axle).

Either of those 2 scenarios are pretty remote ones though and as far as I know there have been no problems with Mustang rear axles nor have I heard of any.
If she bought the car used there’s a possibility that the previous owner could have been whaling away on it street racing or at the strip and weakened something in the rear. Eventually whatever was weakened just gave up.
A mechanically minded person should be able to examine the car and determine what caused this.

Many, many years ago I owned an old Thunderbird (58 model) and the rear axle cracked right next to the differential. It split all the way through but the car simply rolled to a stop; although it was sagging quite a bit in the rear. I don’t think this is what happened in the case of your daughter’s car though.

And the most important thing of all; your daughter was not seriously injured.

This does happen.

My son was driving his Jeep when the rear differential failed. He was doing about 70 MPH when he heard a clunk and the rear tires locked up. Lucky for him when this happened there were no vehicles around him, so as skidded across the lanes he was able to get the vehicle under control without hitting anything.

Guess who replaced the rear diff?

Just be glad your daughter walked away.


Good thing your son was not injured Tester. When suspension parts break or things lock up there’s no telling where the vehicle is going to go.
When the axle broke on my old T-Bird I was only going about 30 MPH so a bit of luck there.

Other than that, the only incident I ever went through was when a rear tire blew out on a BMW motorcycle at 80 MPH. I don’t mind telling you my entire heart was in my throat and it took me a quarter mile of wrestling and praying to get that thing stopped; all downhill on the Interstate and even the slightest application of the brake would cause the bike to go even more beserk than it was.

Still can’t believe I didn’t go down with that one and discovered the rear tire had picked up one of those giant 12" long nails used to attach guttering to eaves on houses. The nail was bent up pretty badly and had absolutely mangled the tire and tube.

The most likely cause of a rear differential failure is all the lubricating fluid has leaked out. This happens when a seal on one of the rear wheels is bad and allows the fluid to leak out. When you get an oil change the garage is supposed to check and refill the differential as part of the oil change service. If they don’t then the owner would never know the fluid is gone and the differential can lock up which is what happened to your daughter.

I haven’t heard that this is a particular issue with Ford Mustangs. It can happen to any RWD car.

An '01 Mustang probably does not have a plug in the differential and Ford calls for service at 100K. A rear axle failure can happen without warning, but it is more likely that there was some unusual noise that should have caused the driver to have it checked.