My 1994 S-10 blazer has a problem with its 4wd. Its an automatic with a 4.3 vortec and push button 4x4. When im driving without it engaged it will all the sudden make a horrible whining sound mainly on the passenger side front. When i engage it while moving it stops instantly. What could be the problem here? I live in Michigan and need my 4x4 for where i live and hunting purposes.

 

It sounds like the axle is not disengaging completely. There is a vacuum actuator located under the battery tray or on the top of the right side fender well behind the battery. It could be bad or the cable that runs from it down to the axle is not moving freely. Unhook the cable from the actuator and push in on the cable which should unlock the front axle and stop the whining. Pulling on the cable unlocks the axle. I hope this helps