The 1947 - Present Chevrolet & GMC Truck Message Board Network

Oh the joys of my truck. What else could go wrong. Oh wait yea that's right the 4wd decided not to work any more. A week ago i had to use 4hi to get to work roads were pretty slick. Get to town hit the first stop light. But of course its Red. Turns green Push the throttle to get going. Moves about 2 feet and i hear and feel a loud clunk from under the truck. Next thing i know it feels like its in 2wd as Im spinning sideways past the intersection. ok that was odd. get to next light. Same thing. and so on past a few more lights. Um ok something is going on here. get to work, Dont think anything of it. go to head home. same thing each light unless i baby the throttle then it stays in 4wd no issues. fast forward to going to work this week. Leave for work roads are pretty slick again. Ok ill deal with the clunk and take it easy leaving intersections. Only one issue now. Go to take off. I have no 4wd. Well what the hell is going on now. No clunk no nothing, just 2wd. At first after doing some research and coming up with transfer case issue causing the clunking I was hearing. To having nothing at all. Do some more research today. Kind of stumped. Could be three things. Tcase actuator, Front end actuator, or the switch. Do how do I figure out whats wrong. Push the 4hi button, light blinks for a couple of secs then goes solid. Go to take off. Nope still in 2wd. Same with 4low still feels like 2wd. Im at a stand still. no clue as to whats going on. Any one have anything like this happen before? and what was the fix for it?