My truck has been running 100% for a good stretch of time, looks like that changed today. Got some snow/ice today and I was in 4x4, backed out of a parking spot and the truck just didn't seem to want to go. I got it moving and let off the gas and it seemed to stop itself. I started moving forward and heard a THUNK from somewhere in the front end. I took it out of 4x4 and it drove just fine the rest of the way home. There was a good amount of snow/slush/ice on the ground. Its dark out so I havent had a chance to check anything out. We are expecting 10-12" of new snow overnight tonight, tomorrow should be fun.

 

it could just be that the 4wheel internals were bound up and the noise you herd was it coming unbound. But that would be the best case scenario. Either way you should check it out so you wont be surprised.

 

I hope you are right, but somehow the best case scenario never seems to work out!

 

Well I dug her out and took her for a spin. Shifted into 4x4 really smooth without any noise, backed out of the driveway and went around the block. No noise. So it looks good for now. I did notice when backing out of the driveway and turning the wheels, I could feel some bumping, but nothing major.

 

water/ice in the front diff perhaps?

 

+1 water and ice in the brakes etc......

 

That happened to me a few years ago. Loud "thunk" but everything was fine.

 

same thing happened to me a couple of snows,i was turning out of a drive to the left.I engaged it as i was pulling out. Has not done it the last 3 times. So just hoping it was kinda bound.