Help with 91 E250 5.8 E4 OF, lost overdrive, all other gears fine no OD light flashing switch works, no burnt fluid ,no metal in pan, no codes, shifts fine manual, just no over drive, doesnt'tslip, wasn't slipping in over drive before it went out hit throttle in over drive bad slip then bad bang felt like some one ran into back of Van hard and stuck in third ever since, my only vehicle, handicap equipped because I'm a pariplegic Mechanic, have rebuilt few C6, and couple AOD but lost on this electronic transmission thanks for any help