the back end of my 1993 cherokee shakes over 60

possable bent rim-bad u-joint-belt broke in tire makeing it out of round.

Maybe it was the slack 15 ft section of chain, tied to your rear axle, Wide Open Throttle Oh ya the other end was tied to a jeep with the front stuck hood deep in a swamp sinkhole... Damn that was wild how your truck flew sideways 15 feet as the jeep stayed stuck... so now you got a shake? talk to ya soon bud..

a u-joint in a rear dana 35? wow...next time do your homework.

have you removed ALL of the mud from inside of your rims? It will throw your balance off and make it shake. Otherwise I'd go with the bent rim idea....unless your trackbar bracket is f***ed up...

Did you have someone pull you out?

you might also have the tires checked for balance after cleaning them. it is possible you lost a weight on one

Over 60 ? that's not tire balance, but the cleaning the mud out ? that idea sounds good before, tire pressure, and a retest.