As long as I've owned my truck, its had a noticeable vibration that starts above 65, gets worse up to about 75, then all but disappears above 80 mph. I've tried everything, wheels balanced, replaced u-joints. Nothing has helped. Read an old thread on here about someone else with the exact same pickup and vibration and he traced it down to the bearings/bushings in the output tailhousing of the transfer case. I checked mine the other day and it does seem that there is some play in where my rear driveshaft slides into the transfer case. Is some play acceptable or should it be rock solid? I was thinking of replacing the the complete tailpiece so I don't have to disassemble it to press bearings out unless this isn't to difficult or requires special tools. Also, anyone have a good source for this? I've checked a couple places and can't seem to find anything.