Hey guys, Ive searched around on here for a while now and cant find a solution to my blazer. Its a 91 4x4, when I attempt to engage the 4wd, it makes a rather loud howling sound from the front left wheel. It only stops when I put it back into 2wd, and shut off the enginge for a few minutes. however my front wheels are not getting power when in 4wd. When I bought the blazer the passanger half shaft was missing....Im wondering if its my actuator switch? or possibly my transfer case.

 

Could be the switch, a vacuum line between the engine & switch or switch and actuator, the actuator itself, a sticky actuator cable between the actuator and the front diff, or a problem with the engagement collar inside the front axle.