you have to always use chalk and mark the driveshaft before you remove it. if you dont have any, then u have to go to the store and get chalk. i have make the mistake before. your driveshaft will vibrate and be toast. and that also goes for if you beat the ujoints real hard and deform it. best thing to do is carefully remove it from the truck yourself, drive it down to a driveshaft shop, pay them the 60 bucks to press the old ones out, press the new ones in, and they will hand you back your driveshaft which you can slap back in the truck.