Section 07-07: Transfer Case, 4x4 System, Service
1996 F-150, 250, 350 (4x4), and Bronco Vehicles with Manual Shift Transfer Case; All Bronco and F-150 4x4 Vehicles with Electronic Shift Transfer Case Only Workshop Manual
DESCRIPTION AND OPERATION

Windup and Delay Shifting Out of 4-Wheel Drive

NOTE: To determine if driveline windup is causing delayed shifts to 2WD, jack the vehicle or lift it on a hoist with the wheels free to rotate. This should release the driveline windup, if it is present, and the transfer case (7A195) will complete its shift, if windup is the concern.

NOTE: Vehicles vary in terms of how "tight" they are. Some vehicles have a lot of "give" in the system. Softness in suspension and mounts will allow the driveline to absorb more windup before it affects performance. If driveline windup occurs, the system will tighten like a giant rubber band until the tires start slipping. A "tight" vehicle will signal the windup sooner, usually by a lot of chattering noises.

A delay or a failure to shift out of 4WD may be the result of driveline windup or extremely cold temperatures. In 4WD, windup can develop, especially if the vehicle is operated on hard, dry surfaces or in tight turns. The driver may select 2WD, but the shift doesn't take place even though the 4WD light goes out. Also, as long as the transfer case doesn't shift, the hubs remain locked and the vehicle remains in 4WD. If windup in the transfer case is severe, even backing up may not release it.

In order to return to 2WD under these conditions, two things must happen. First, if the transfer case doesn't shift right away, the vehicle will have to be driven in 4WD until the windup is relieved or until the axle warms up. Second, when it does make the shift, the driver will have to stop the vehicle and go straight in the reverse direction for at least ten feet to unlock the hubs.