Did I kill my Diff?

[blown240]

A few days ago I noticed what sounded like a tin can being dragged randomly from my 04 Yukon XL. It was only ever so often. So I got under it to make sure it wasn't an exhaust heat shield or something. Then yesterday as I was backing out of the driveway and turning there were 3 large bangs from the rear end... I had to get to appointment so I drove it anyway and took it straight to the shop after the appointment. Driving over it was making some noise, but coming home it wasn't at all. The shop said the old diff oil was really bad, and they cleaned out the diff and put in new fluid.

Now, this morning, the noises are all gone, but there is a vibration whenever im above 15mph and accelerating lightly. Its not horrible, but defiantly noticeable.

Any thought as to whats going on? Did I kill my diff?

 

[wjburken]

A few days ago I noticed what sounded like a tin can being dragged randomly from my 04 Yukon XL. It was only ever so often. So I got under it to make sure it wasn't an exhaust heat shield or something. Then yesterday as I was backing out of the driveway and turning there were 3 large bangs from the rear end... I had to get to appointment so I drove it anyway and took it straight to the shop after the appointment. Driving over it was making some noise, but coming home it wasn't at all. The shop said the old diff oil was really bad, and they cleaned out the diff and put in new fluid.

Now, this morning, the noises are all gone, but there is a vibration whenever im above 15mph and accelerating lightly. Its not horrible, but defiantly noticeable.

Any thought as to whats going on? Did I kill my diff?

Did the shop inspect the gears in your differential at all or just change out the differential fluid?

 

[blown240]

They just changed the oil. Its a small local shop and they dont do more than a fluid change. They said they would have to outsource any other work...

 

[wjburken]

They just changed the oil. Its a small local shop and they dont do more than a fluid change. They said they would have to outsource any other work...

Did they at least comment on whether or not they found metal chunks or shavings in the fluid?

I would either crack it open myself and take a look at all the teeth to make sure I didn't have pieces missing or get it to a shop that is set-up to deal with a rear differential and have them take a look.

 

[blown240]

They said there was alot of metal shavings in it.

 

[OR VietVet]

You likely have some bearing and gear problems in there causing the noises and the vibrations. Have a professional rebuild it because it is not for the DIY mechanic unless you know what you are doing. Or, you can get a used diff, same gear ratio, and swap it out. That is something the typical DIY tech can do. The shop you used had to remove cover and expose the bears when they drained it, unless they sucked it out and that method SUCKS, IMO, because you don't get to see anything that caused the fluid to look "really bad". Make sure you inspect and replace as needed the u-joints on the driveshaft, too. Use the correct diff fluid that is listed in your owner's manual or the equivalent. If you do the axle change out make sure you bleed the brakes properly. Swap your brakes and rotors over if they are in better shape and it would be a great idea to go ahead and do the axle seals while all apart like that.

 

[OR VietVet]

They said there was alot of metal shavings in it.

The disintegrating metal in there is causing the shavings and the fluid to be grey. YECH!

 

[blown240]

I called my local differential shop. He quoted $800 to put in a fresh open diff. I would loose the limited slip, but I'm not sure if thats an issue in SoCal...

 

[wjburken]

I would go with a limited slip again if it was me. I have never been happy with an open diff. I can notice the difference even in taking off from a light on wet pavement sometimes.

 

[blown240]

He said he can do a True Track for $1000.