Hey Guys, quick question. My driveshaft moves up and down. I mean up and down towards the truck or the ground. The edge of the outside piece will bang the inside piece. I was told by a reliable source it is the slip joint on the shaft and the shaft would have to be replaced or it could be built up with weld and fixed. Anyone have a problem like this. And is the driveshaft unusable. I have it off my truck right now, but I just had an offer to go wheel tomorrow and really wanna put it back on and go. Any thoughts are appreciated as always.