I have been getting a strange feeling in the drivetrain upon startup from a complete stop. It feels like something is unwinding or crunching without really making the noise. I have always had a clunk until I regrease the driveshaft spline and then it is gone for awhile. This is different. So today I crawl under the truck (1997 F150 4x4 88,000 miles) and start grabbing different parts trying to find movement, noise whatever. I grabbed the driveshaft next to the transfer case and pushed up toward the truck floor. I heard a slight clunk and also could see the shaft (drivshaft) where it goes into the transfer case move up, not in or out but up and down I'm guessing about 10-15 thou. There is no oil leaking at the rubber flange and seal area but this seems like quite a bit of play to me. Any ideas what I have going on if anything and if so is this an easy repair? Thanks for any ideas and opinions.

 

Are you sure the play isn't in the u-joints?

 

Ya, I can look right at the shaft where it goes into the transfer case and watch it move up and down as I lift,pull it. There is a rubber sleeve that protrudes out from the transfer case output and I suspect there has to be a bearing behind it? When I move the shaft up and down I can generate a clearance between the shaft and the rubber sleeve. I changed the u-joints about 35,000 miles ago and installed greaseable ones which I grease twice a year. There is definetly some play between the shaft and transfer housing/bearing.

 

Update. I called a buddy who lives upnorth and owns a 97 F150 like mine. Told him the issue. So he went out and did the same thing with his, pushed up and down on the transfer case output shaft. He got the same movement at the housing that I'm getting. He was surprised as well. Hard to believe that much movement is normal. Anyway he contacted a friend of his with same truck only a 98, he did the same thing as well, same results. So its normal...Just wanted to let anyone who may have been wondering what the outcome is. I still have something going on that I have to find. Just prefer to find it before it becomes an issue when I'm in the middle of nowhere while upnorth deer hunting.