Download 2003 Ford F150 Driveshaft U-Joint Rear Replacement – Step 1 — Here is a view of the rear U-joint assembly. It is connected to the driveshaft via the flange yoke. It is bolted to the rear axle at the drive pinion flange The front U-joint assembly connects the drive shaft and the slip yoke. The slip yoke just slides into the transmission and meshes onto the gear with it internal splines. Use a chisel, or similar instrument, to index the flange yoke and the pinion flange. All that does, it makes a mark across those two pieces. This will assure that the drive shaft will be mounted in the same way once the repair is done. Step 2 The damaged U-joint is clearly visible. There are four bolts that connect the flange to the yoke. The bolt heads require a 12mm 12point socket. A 6 point socket will not fit, and a box end wrench will not generate enough torque. Use a 12mm 12 point socket and a 16 inch breaker bar will generate enough torque to remove the bolt. Here a 1/2″ drive socket set is used. 3/8″ socket set may work as well, but the larger drive set will tolerate a bit more torquing.