i've got a 10 bolt out of an 02 trans am and when ever i do a burnout i hear a nasty popping sound that rattles the whole car. i jacked up the rear and noticed i can turn the passenger side tire without anything happening it spins free for the most part but every now and then you feel a little drag. I pulled the diff cover and everything looks good not even any shavings on the magnet. got any ideas.

With the Zexel Torsen differential, unless there is some resistance, one wheel can spin freely - there has to be torque applied to both wheels, with one having less resistance than the other, in order for the differential to apply power to the "free wheel". Thus, having a wheel jacked in the air will not allow the differential to apply power, and it will free-spin. In other words, you can't apply enough force to a spinning wheel by hand in order for the differential to apply power to that side, if that makes sense.

I'm not totally understanding it either, but it kinda makes sense (intuitively anyhow) by reading about it:

http://en.wikipedia.org/wiki/Torsen#How_they_work

Doesn't solve the issue, but explains why you can't feel the resistance you are expecting with a wheel jacked up (especially the pass wheel).

I'd maybe look into U-Joints, maybe the pinion nut/seal/crush sleeve, or tranny and/or motor mounts. But again, I'm certainly no expert. Good Luck!

Solution... Stop doing Burnout.

Which differential do you have? If you have the Torsen differential then I'm not going to be much help. I don't have any real experience with them. I would suspect that there is something wrong in the differential that is causing this problem. I doubt that it would be stripped splines because the splines are stronger than the shaft. I also doubt that it's a ring & pinion problem. The first place I would be looking is the differential.

I have the Torsen differential. I checked my u-joints they have no play and they're relatively new( 1 month) my trans mount is poly and all the bolts are good and snug. what im interested in is how do I check the pinion nut and crush sleeve. can i do it with the rear in the car.

and stop doing burnouts, what good is TPI for

REmove the drive shaft and put a torque wrench on the pinionnut. The nut is 1 1/4 inches, so you will need a socket this size. Set the torque wrench to 150 and see if the nut is this tight. If it is then the nut isn't loose. If the nut turns at 150 foot pounds then you might have a spacer problem or the nut was just loose. Check the bearings by pushing up and down on the yoke. If the yoke moves in any direction other than rotation then the bearings may be bad.

Just wanted to give an update on what the solution of this was and it turned out that the 2 side welds on the spring perch were cracked and them rubbing during the wheel hop was the loud popping sound and they were also the cause of the wheel hop. glad i caught this before that last weld gave out