When u shift to 4wd there is a vac. Servo under the hood. This has a cable that locks the front hubs. Sometimes the little clip from the servo to the cable. The clip brakes at the servo. When you switch to 4wd the servo sucks in and with that broken clip it doesnt pull the cable to lock the front hubs. Just go to the cable. Pull it to lock the hubs use vice grips to hold the
cable. Then test the 4wd. If your truck doesnt have this sys. Mail 2CarPros Jack. My sons had a 84 chevy it had this type sys.I cant see them redisigning a whole different sys. Gl
Wednesday, August 8th, 2012 AT 4:24 AM