Back in January this year my son had some grinding noise from his right rear brakes, turned out to be the axle broke where the clip holds it in. The mechanic that repaired it is a neighbor who owns an All Tune & Lube, and suggested I order the parts direct from Summit to save some money.

After we got the parts they replaced the axles, carrier and both rear brakes. Last week, my son had the same grinding noise coming from his right rear. This is after driving the car for 3 months without incident.

I had him take it to the mechanic immediately. The mechanic called next day and said the right axle is loose, not broken, but moving in and out about ¼”+, allowing the rotor to rub the brake calipers. They took the differential cover off and the axles were fine, just loose. They spent the next day diagnosing the problem and first call today said that the axles from Summit were bad, probably milled incorrectly. They purchased new clips from Ford, and the Ford clips would not fit the Summit replacements (these are Ford racing replacement axles?).

They said they spoke with a local Ford Dealer and suggested we purchase Ford replacements, install them, and see if the axles from Summit are bad. I called Summit and they said they would allow the return if the axles were defective, no problem (got to love Summiit). Well, I called the mechanic and said go ahead and order the Ford axles and if they fit, I would buy them, if not, I wouldn’t. He said Ford would not allow a return, as axles are special order. I told he I needed to consider what’s going on here and call later.

A little while later, the mechanic calls and wants to know if I am the original owner, which I am not. He then suggested that the axle might not be a GT axle; it could be a Cobra axle, which requires different axles, carrier and brakes.

I was upset that they didn’t discover this when they made the original repair. The mechanic said it was assembled by a fellow that does not work there now, and they have no idea how he put it back together the first time.

So, the mechanic is going to research the axle to see if he can locate a serial or part number that would identify the axle as either a GT or Cobra and then advise how to repair it.

That’s the story so far.

If anyone has any experience with 94 Mustang rear ends and could advise me on how not to get screwed, I would appreciate your advice.

The Cobra Independent Rear Suspension, taken from the Thunderbird, is much different than the integrel housing axle in a GT. But, the ring/pinion and diff are the same. The 7.5 axle found in some Mustangs uses the same axles as the 8.8 Take both axles out and compare them looking closely at the button on the end which the c-clip engages. To have an excessive amount of endplay in the assembly, and assuming all the parts are there and correct, then the clutch pack in the diff is bad.

Without specific information and measurements everyone is just guessing at your problem.

I did get some more information today. Called the manufacturer "Superior Axle" and they referred me to a Mustang performance shop in CA, who measured the groove in the axle at 4mm. The groove in the axles we received are 4mm. They told me to use the original Ford clips and the movement would be in the axles until the rims are bolted on. Our movement is after the rims are bolted on.

Back to the drawing board!

Like Imsport said, the clutches in the trac-lok are probably toast. I would also check the side gears and the cross pin for wear.

I don't think that play is the issue. If they didn't have the play you wouldn't be able to slide the axle inward to get the clip out. Most 8.8s I see have a lot of play compared to a removable carrier axle. The only way there would be no play is if the axle butted up against the cross shaft, a 1/4" is not that much in my opinion. One of the biggest issues I run into is the bearings ride on the axle without an inner race, so if the bearing starts failing it chews up the axle. I wonder if that might be going on. Maybe the bearing was damaged when the axle broke and caused it to tear up the surface on the new axle. I'd pop the axle out and inspect the axle surface where the bearing rides as well as the bearing itself. They are miniscule compared to 8" and 9" bearings. I have seen, as mentioned, the posi plates burned up and creating noise. Another issue that seemed weird but was verified by replacement was the ABS sensors being broken/disconnected. It caused a pulsing of the brake which transmitted through the axle and caused what sounded like bad posi plates. Installed new sensors and it was gone.

94 mustangs,gt and cobras,both use the same rear.the only parts that are different are the calipers,rotors and pads.cobras didnt get irs rears untill99,so the axles you have shouldn't be the problem.check the diff.

Fixed, don't know what the final analysis was, but the shop called late Saturday afternoon and said it was done. We picked it up, drove it and no rubbing, brakes are fine, rear end seems fine. The mechanic wasn't there when we picked it up. No charge, so it must have been something they didn't do right the first time.

Glad you got it sorted & with no charge.