Can any of you maybe tell me what's most likely wrong with my car?

69,000, "All-Wheel-Drive or 4X4?" :)) is he playing games or what, You can't drive without a Drive-Shaft. "AWD or 4X4" there are 'Two" Drive-Shafts, Long shaft to the Rear Axel you need to Drive, Short Shaft in front running from the "Transfer Case to the Front Drive Axel" that one you can remove for a short time to get it to a repair shop. Could be the transfer case or Front Drive Axel that is going bad? Have you noticed any differences in the way the Truck Steers? Try Having (NOT by the BF) the Short Drive-Shaft to the Front-Drive-Axel pulled and see if the changes things, if it does put that one in the back of the Truck and (Dealer Might Be Best) Drive to the Shop. If it is a Drive-Shaft Problem "Which it may be" it should be Moved (Towed) on a Flat Bed! Vibration will still happen with a Conventional Tow.