Do you have the FSM? A line pressure check would be a good first test.

Assuming you have the gear selector working and the flex plates bolts are in.

A good transfer case check is to see if the rear drive shaft is locked up with the tranny in park. You will want both rear wheels off the ground. Put it in neutral and you should be able to turn the drive shaft.

Kevin

87 Turbo Intercooled Raider, roller cam, torsen rear diff, LSD front diff, lockup auto with modified converter, V6 brakes, low transfer case gears...