so i was driving my truck the other day and just coasting. when i got back on the throttle it was like it was in neutral. i pulled over and my overdrive light was flashing i shut the truck off and started again. i pulled away and was doing 30 mph at 3000 rpm. i pulled over called a buddy and towed it home. now it does not go forward or backwards when in gear. i lifted the rear end off of the ground and the tires would spin. PLEASE ANYONE HELP im not sure what it is exactly. Thanks for any help

__________________
2001 Ford Ranger 4.0 SOHC, cold air intake, Dana 30 swaped, custom Y-link long arm lift, stretched 2", 35x12.5x15 tires, Ext. cab, step side, green