Well folks I have taken my truck to three different shops to get the front end looked at. I have a grinding noise or sometime banging sound and the 4wd does not work. The first place tighten some bolts that hold the front diff. Everyone else could not find any other problems. I recently was backing up to my lower garage which is on a steep incline and the front tires would not spin while locked in along with a loud grinding noise. After that drove out to the snow cover road nailed it and everything spun as it should with no noise what so ever. I am at a lose and very pissed because I love this truck an am the original owner. So I know the history which has been babied in my opinion. Just clicked 27,000. Any help would be greatly appreciated! Just went to Montana and had no problems in 2wd clocked on 3000 miles, but did run into the issue when we were out there.