Vibrations or banging noises in the rear of your truck when shifting gears may indicate a worn or damaged U-joint. If you need to replace a U-joint in your truck, you can get the joint at most auto parts stores as well as renting any tools that you need. A worn U-joint that is not repaired will eventually damage the differential, the transmission or fail completely and damage the drive shaft. You can change a U-joint at home in the driveway or garage and save yourself some money in the long run.
Place a jack under the rear differential of your Frontier and raise the truck until you have it high enough to comfortably work under it. Support the truck on a set of jack stands, making sure the stands are on level ground so the truck does not shift or move.
Place the transmission in neutral so that the drive shaft will spin freely by hand. Mark the drive shaft mounting flange and the mounting flange on the differential with a paint marker before disassembling them so that you can reassemble them with the same orientation.
Remove the four mounting bolts from the rear mounting by removing the nuts from the back side with a wrench and pulling the bolts out of the flange. Drop the rear of the drive shaft down below the differential and slide the drive shaft out of the slip joint at the rear of the transmission. Remove the drive shaft from under the truck.
Remove the U-joint retaining clips from the drive shaft on both ends. There are eight clips, four on each end, and they can be removed by squeezing the tangs on the clip together with pliers then lifting them out.
Remove the U-joint by pressing the caps out with a U-joint press. If you do not have a press, you can rent or buy one at most auto parts stores. The press looks like a big C-clamp and works much the same way.
Position the fixed end of the U-joint press over one cap and the threaded shaft on the opposing cap. Turn the threaded shaft with a socket and ratchet, pushing the cap through the drive shaft yoke. Flip the press over and push the U-joint back the opposite direction to remove the second cap. Repeat this process until you have removed the U-joints at both ends of the drive shaft.
Position the new U-joints into the shaft working on one end at a time. Use the U-joint press to push the caps into the yoke and onto the new U-joint.
Install the retaining clips into the yokes outside the caps. Be sure they sit in the groove on the inside of the yoke and completely seat when installed. If the clip is not fully seated in the groove, the spinning shaft will dislodge it and the caps will work loose, causing a vibration or failure of the joint.
Position the drive shaft back under the truck and slide the slip yoke into the transmission. Be careful not to damage the oil seal as you slide the shaft in. Align the painted marks on the rear yoke and the differential mounting flange and insert the mounting bolts through from the front of the flange. Install the retaining nuts on the back of the flange.
Hold the nut on the back of the flange with a wrench, then tighten the bolt from the front to 60 foot-pounds with a torque wrench. Repeat this for all four fasteners. Raise the rear of the truck with the jack and remove the jack stands. Lower the truck to the ground and test drive the truck.
