I have a 96 2500 that started to make popping noise going down the road with no load. Sounded like u-joints but got out and looked and could not see a problem. Drove about 5 miles home and got under and checked and the u-joints are tight but the rear diff is low on oil. Left rear axel seal is leaking. Put more oil in this morning and tried some slow circles in the yard and it snaps and pops and feels like it is trying to rip the gears out. Do I need oil modifier or something as I have read on some of the threads. Or should I drive it some more to get the oil worked into it better?

 

Fricton Modifier is available at the Dealer.

Try adding a tube and doing some SLOW figure 8s in your local parking lot to get it worked into the clutches.

 

Tried that and now it won't move at all. Guess I finished off the gears in the rear end.

 

So drive shaft spins, but truck doesn't move?

Sounds like time to pull the dif cover and see what happened.

 

Sounds like pinion gear broke. Pull cover and see if gears are broken, Good Luck

 

If its binding and popping going straight then the locker portion of the rear is not doing anything so modifier wouldn't help (but I could be wrong). Sounds like it maybe to late for it though. I would pull cover and check for extra loose parts that maybe floating and jambing the crown and pinion. May also be pinion bearing is going for a holiday but should get worse when right foot aplyed. Lots of bearings in the back end to check. Better to check in the drive way then sweaping them up off the freeway.

 

Change diff lube and add at least one bottle of anti lock lube additive. Do figure 8's and drive for several days. Add another bottle of additive if not resolved. If still not resolved, the diff assy will need replaced or traclock overhauled. JMHO