I have an 04 RS. When accelerating hard with the wheels turned, I tend to get a hopping which gets progressively better with the wheel straightened out. It's particularly noticeable in an autocross situation, but also on the road course in tight turns. I've had this all season and just drive around it. At yesterday's very technical autocross I had it repeatedly due to the course design and I was pushing harder than usual and somewhat staying in it even with the diff fighting me.

I'm suspecting something may have gotten damaged yesterday though because in one of the fast sweepers, I was on the rev limiter when I wasn't going fast enough to get on the limiter (i.e., wheelspin). And when I went to change tires, the breakaway torque on the front diff was much less than usual. With one front tire on the ground and one in the air, I couldn't torque the wheel lugs on the suspended wheel, which I ordinarily can do due to resistance of the diff. The wheel just turned. I measured the breakaway torque and it was around 50-55 ft/lbs, whereas ordinarily it's 85+.

If we had clutch-type front diffs, then I would suspect that I smoked the diff, but since it's a helical, I can't imagine what would do this? Bad fluid? Overheated fluid? Stripped gears? I need to do more diagnostics, but haven't had a chance yet.

When I drive the car on the street, all seems normal. No grinding or anything.

Has anyone encountered anything like this before? Any suggestions on diagnosis?

Thanks.

 

It couldnt be that youre just over-driving the car into corners would it? the difference in breakaway force was probably that everything was still hot in the tranny. technically, you shouldnt be able to torque the suspended wheel anyways. helical differentials act like open differentials once grip at one wheel is lost.

 

I had an 03 with the ralliart diff and never noticed hopping. I also couldn't torqe a wheel with it in the air.

If you want to test the diff ture the wheels very sharp and pound on the throttle. If only the inside wheels spins then the diff is dicked up. One thing I can tell you is there was a night and day difference between the open diff and the LSD. If you diff was jacked you would know it when aggressively driving the car. It would also dent to plow alot more.