Can uneven tire wear trick the DEM to think slippage?

**el_loco** · 01-21-2015, 02:37 PM

Trying to track down a clunk occuring while cruising between 20 and 35mph. 2004 with 113k on the clock. After driving and examining my car for the source of the clunk, my indy mechanic found that my car needed a DEM software update to solve the clunking issue (apparently there's a bulletin about the issue from Volvo). The update was installed but did not fix the issue. As I was browsing forums I read that if the wear is different from front to back tires, the difference can cause the DEM to read that there is slippage and tell the AWD system to engage, perhaps causing the clunk I am feeling. Does this sound feasible?

**el_loco** · 01-22-2015, 01:50 PM

I am continuing to research and it seems that there are a number of posts internet-wide where uneven tire wear, especially more worn in the front, caused issues for the AWD system. I understand the older (<2002) systems were more susceptible to damage. My car being a 2004 gives me hope that 4 new tires would correct the issue, but I am hesitant to spent the few hundred bucks if I am not somewhat confident that they will correct the issue. I'd love to hear whether anyone here has experienced any weird symptoms resulting from tmis-matched or unevenly worn tires?

**Willy** · 01-22-2015, 02:24 PM

Although a big difference in tire wear front to back is certainly not ideal,
I would be surprised to learn this would turn out to be the cause of the clunk you feel.
Even if so, I don't think that the engagement of the AWD system should be clunky.
Willy

**el_loco** · 01-22-2015, 08:52 PM

Any ideas on a likely source for the clunk? Mechanic said next thing to replace would be the rear diff fluid pump. Failing pump a possible or probable culprit?