First, sounds like your tranny is on its way out the door. The 42re behind the 4.slo is a POS. Decent motor, horrible trans.
Second, there is a recall for the airbag that was just released in November. Last I heard, the dealerships still dont have the parts to fix the issue, but you should probably look into that.
Third, disconnect your battery, clean the terminals, clean the terminals again, and when you think they are perfect, clean them one more time.
2002 Overland - 4.7 HO, "Select-Drive", 4" RC long arms, TAG front winch bumper, 32" BFG KM's, 3" exhaust, Magnaflow hi-flow cat, Flowmaster 50 series