87xj wheel hop issues

So I went out and did a little wheelin last night and came across an issue when bogging through some
Soft sand and other loose gravel in 4wd and 2wd when I'm loosing traction it seems that the jeeps attempts to regain traction are causing the wheels to hop violently loud noise inside and out of the jeep boom boom boom boom when I retraced the trail I noticed many small whoops created by my jeep apparently from this odd violent wheel hop .. I've already replaced the rear shaft u joints what else could this be.... FYI 87 xj renix 4.0 selec trac tcase D44 rear axle

http://answers.google.com/answers/threadview/id/435184.html

Essentially, slow down and air down.

This seems to make sense.. My friend beasted through the same sand.. But his jeep is in very new shape and very new shocks... What I'm thinking is my shocks are bad

more likely your rear leaf springs are done.

Go pull some from a much newer junkyard XJ that hasn't sagged, or just get some aftermarket replacements.

If you go look closely you may see an "S" shape bend in the front half of the spring, that's bad, or they may be nearly flat just sitting, that's bad.