Uneven tire wear -- bad rear diff?

[rlrhett]

I've noticed an odd thing on my 2002 V70 XC. One rear tire has worn considerably more than the other. I have heard conflicting opinions on why that might be. One camp has it that this is fairly normal for a car with limited slip rear differential that is mostly driven in city (as opposed to highway) driving. The other camp says the diff is not working properly and appears to be locking the rear wheels together. There is no noise and the car tracks true.

Here are pictures of the tires. Driver's side rear tire looks fairly good, while the passenger side wheel is worn. Is this indicative of a problem? What should I do to test to confirm a problem in the diff?

IMG_3556.jpg (30.28 KiB) Viewed 4907 times

IMG_3555.jpg (27.81 KiB) Viewed 4907 times

[oragex]

I assume you have installed both tires from new? If so the worn one gets all the traction while the other one is just rolling. Do front tires wear as little as the one in the upper picture?

[rlrhett]

Yes, they were put on at the same time from new. I always do them in twos, same make model and size for all four. The fronts have a tendency to wear out faster, so at some point when money was tight I changed them out without changing the back. Since then they have been out of sync, so I can't really tell whether the fronts are wearing like the driver or passenger side of the back. However, their ware is even passenger to driver side.

Someone told me that the problem was that as the car goes around right corners the outer wheel is spinning faster. The diff is not letting the inner tire spin more slowly causing it to essentially skid around the corner. Nothing but conjecture. No test has been done. Don't know what or how I would test. But I throw that out there as a data point.

[jonesg]

What about getting the alignment checked.

[rlrhett]

What about getting the alignment checked.

Good suggestion. Some times it is the most obvious things. Ill check it this week and post back.

[DrBoost]

If the tire was, essentially, dragging due to a bad differential, you'd hear howling often. It would also cause some issues while traveling in a straight line. The differential fluid would also be burned as well. I suspect alignment. The outside is worn more than the inside, that's alignment for sure (camber). The tread is also warn across the entire width, that wold make me suspect the toe is out of spec as well.
Let us know what you find.

[kcodyjr]

Also, resolve it quickly. Having tires with different diameters stresses the hell out of the AWD hardware.

Worth checking that differential fluid if you haven't already. It might stink like last week''s trash.

[shiloh51933]

Also, resolve it quickly. Having tires with different diameters stresses the hell out of the AWD hardware.

Worth checking that differential fluid if you haven't already. It might stink like last week''s trash.

+1
Have you been rotating tires every 5K?

[vtl]

Too much toe-in.

[abscate]

Bad alignment. Look how badly the outside edge is worn relative to inner

Toe in most likely, camber possible but that will probably mean bent suspension parts