Ticking noise

[led4evr1978]

I have a 04 XLT 4.0 with 98,000. Rear diff started whining and not sounding so healthy a couple of months ago. Once I figured out where the noise was coming from, I orderd a rebuilt diff from ericautopart, a member on here. (Which in my opinion, is the way to go if you're not a mechanic and unable to rebuild the diff, like me. Free shipping of the rebuilt diff, and free shipping of the core, the bad diff, can't beat it.) Anyway, a buddy of mine and I put the new rebuilt diff in, and everything was fine. Then a week later, another damn noise is occuring. This time, the best I can explain it, is it sounds like there is a baseball card in the spokes of my bike. Click click click, almost like something is rubbing, but not quite. Can't quite place where it's coming from. From the drivers seat it sounds like it's coming from the front, from the passenger seat it sounds like it's coming from the rear. Can't tell. Noise is constant when vehicle is moving, clicks faster the faster I go. We jacked up both ends of car and put it in drive and got going about 20, no freaking noise. Also, doesn't get better or worse when turning or braking. I know it's hard to diagnose something without seeing it or hearing it, but has anyone ever had a noise like that? My buddy thinks it could be a hub bearing(wheel bearing?) Any suggestions would help. Thanks

[joachimf]

Well, removing the diff means replacing the fluid....

I had a clicking and clonking noise on our 2002 XLS 2WD in summer time after the fluid had been changed in spring, diff is a 3.73 LS.

After a little googeling around I found out this kinda noise is a common prob with GM diffs with LS clutches. After going through some GM technical bulletins I got the info adding more friction modifier than originally requested.

So I tried this and added more XL-3 to the 85W/140, noise is gone. Hope this helps.