rear end supposed to be open but operating like LSD
My door code for the rear end is 86 which is 3.73 open on 2001 Ford ranger. The rear tag is also 3.73 with no L. When both rear wheels are off the ground and running in gear the rear end spins initialy but stops. When not running I van spin it initialy but it also stops. My truck is a 4x2, 5 speed, and 4cyl engine. The truck runs fine when wheels are on the ground. Please help.