Mustang Question

[wingnut]

Daughter's 2000 mustang with 108K is making a noise in the rear. Opened up the rear and all the gears look worn but no damage. Looked at the wheel bearings and as best I can tell they look and feel OK. Any one have this problem with a ford 8 inch rear? Have not pulled the pinion bearings yet but there is no leakage from the seal and no slop in the shaft. Can't figure where this noise is coming from so I'm open to any ideas.

Thanks
Dave

[eroellig]

Re: Mustang Question

Originally posted by wingnut
Daughter's 2000 mustang with 108K is making a noise in the rear. [...] Can't figure where this noise is coming from so I'm open to any ideas.

Thanks
Dave

Dave,

Different rear end (Ford E150) and I pulled it hard with a 29' travel trailer, but I had rear end noise once. The cause was the surface of the race for the pinion bearing. The surface was breaking down and getting rough in one spot (and getting bigger). The noise was a periodic sound that was faster than wheel RPM (it was the pinion after all) and definitely related to ground speed and engine loading. There was no fluid leakage. You coudn't really feel it turning the pinion by hand. It took a load (like accelleration or hill climbing) to push the forces against the race hard enough to really make a sound.

What kind of noise do you hear?

Eric

[bandet01]

the rearend is a 7.5 and i would say it needs a new ring and pinion and a posi unit rebuild

[wingnut]

This is a consistent cyclic noise that dose not seem load related. Its also at about wheel speed frequency, rough bearing surface sounds about right. It has gotten worse over time. Time is the problem. She has to be back in Charlotte on Monday and I have to be in Virgina Beach that day also. We live in Havelock which is a pretty small town. Small enough that if you can't buy what you need at walmart or auto-zone you have to import it. I'm going to try and find some new wheel bearings & seals, put it back together, fill it with Mobil 1 and turn it loose for now. If the noise is still there it will have to hold up until I have more time. There are no metal fragments or chips in the housing or old fluid just noise. Maybe the new wheel bearings and fresh fluid will quite it down some. I'll let you know. Thanks for the responses

[LoserShoes]

Did you check out the U joint ? Replace that first and see what happens.

Steve

[trbig]

I was going to say U-joint also. I lost a rear U-joint on a Mustang once doing close to 150mph. Talk about tearing things up before it got out from under the car! lol. Even if that isn't the problem, after 108k, it's due anyway. Change both the front and the back... pretty cheap insurance.

Tod

[wingnut]

Back on the road

R&Red the wheel bearings and seals. Cleaned everything and put in new fluid. Double checked the U joints everything felt smooth. Checked the backlash in the ring and pinion. .016 of lash which is double the stock spec. That's pinion gear wear with possibly some pinion gear bearing slop to boot. Biggest noisemaker was the wear in the spider gears to shaft. You can hear the spiders meshing when you turn the axles. 016 is what they set rears to for racing short track around here so I think this thing will hold up for a good while its just going to be noisy. If it had measured .020 I'd be in the junk yard right now pulling a rear. Test drive showed noise much better so back in service it goes until I can round up some parts and get a slot in the honey do list to fix it for real. Thanks for all the suggestions and ideas

Dave