When my 88 cherokee is in 4WH and i mash on the gas for a second or so then let it coast it does this awful BANG! it didn't happen in 4WL but i didn't want to keep trying... i do have a Posi-Lock on the front if that even matters. The BANG seemed like it came from more of the drivers side area, fur sure in the front. Any help is awesome help!!

 

If it were on the passenger I'd say it was the vaccuum disconnect for the axles...could still be. Who knows though it could be the posilok disengaging.....don't know much about those earlier Dana 30's

Does it still function the way it should in 4H and 4L? Were you turning or anything at the time you heard it...might be the Power steering setup, trac bar or pitman arm...just guessing though

 

was not turning just going straight, the 4wd still work normal in high and low. when i let it coast after giving it gas is when it does it but then it will pick back up normal as soon as i go again.