The driveshaft is the means by which the power from the engine and transmission (in the front of the car) is transferred to the differential and rear axles, and finally to the rear wheels.
The driveshaft assembly incorporates two universal joints-one at each end-and a slip yoke at the front end of the assembly, which fits into the back of the transmission.
All driveshafts are balanced when installed in a car. It is, therefore, imperative that before applying undercoating to the chassis, the driveshaft and universal joint assembly be completely covered to prevent the accidental application of undercoating to their surfaces, and the subsequent loss of balance.
- Mark the relationship of the rear driveshaft yoke and the drive pinion flange of the axle. If the original, yellow alignment marks are visible, there is no need for new marks. The purpose of this marking is to facilitate installation of the assembly in its original position, thereby maintaining proper balance of the driveshaft assembly.
- Remove the four bolts or nuts which hold the rear universal joint to the pinion flange. Wrap tape around the loose bearing caps in order to prevent them from falling off the spider.
- Pull the driveshaft toward the rear of the vehicle until the slip yoke clears the transmission housing and the seal. Plug the hole at the rear of the transmission housing or place a container under the opening to catch any fluid which might leak out.
UNIVERSAL JOINT OVERHAUL
- Position the driveshaft assembly in a sturdy vise.
- Remove the snaprings which retain the bearing caps in the slip yoke (front only) and in the driveshaft (front and rear).
- Using a large punch or an arbor press, drive one of the bearing caps in toward the center of the universal joint, which will force the opposite bearing cap out.
- As each bearing cap is pressed far enough out of the universal joint assembly so that it is accessible, grip it with a pair of pliers, and pull it from the driveshaft yoke. Then, drive or press the spider in the opposite direction in order to make the opposite bearing cap accessible and pull it free with a pair of pliers. Use this procedure to remove all bearings from both universal joints.
- After removing the bearings, lift the spider from the yoke.
- Thoroughly clean all dirt and foreign matter from the yoke area on both ends of the driveshaft.
When installing new bearings within the yokes, it is advisable to use an arbor press. However, if this tool is not available, the bearings should be driven into position with extreme care, as a heavy jolt on the needle bearings can easily damage or misalign them, greatly shortening their life and hampering their efficiency.
- Start a new bearing into the yoke at the rear of the driveshaft.
- Position a new spider in the rear yoke and press (or drive) the new bearing cap 1 / 4 in. below the outer surface of the yoke.
- With the bearing cap in position, install a new snapring.
- Start a new bearing cap into the opposite side of the yoke.
- Press or drive the bearing cap until the opposite bearing-which you have just installed-contacts the inner surface of the snapring.
- Install a new snapring on the second bearing cap. It may be necessary to grind the surface of this second snapring to facilitate easy entry into its proper position.
- Reposition the driveshaft in the vise to facilitate work on the front universal joint.
- Install the new bearing caps, new spider, and new snaprings in the same manner as you did for the rear universal joint.
- Position the slip yoke on the spider. Install new bearings and snaprings.
- Check the reassembled joints for freedom of movement. If misalignment of any part is causing a bind, a sharp rap on the side of the yoke with a brass hammer should seat the bearing needles, and provide the desired freedom of movement. Care should be exercised to firmly support the shaft end during this operation, as well as to prevent blows to the bearings themselves. Under no circumstances should a driveshaft be installed in a car if there is any bind in the universal joints.
- Carefully inspect the rubber seal in the end of the transmission extension housing. Replace it if it is damaged.
- Examine the lugs on the axle pinion flange and replace the flange if the lugs are shaved or distorted.
- Coat the yoke spline with lubricant.
- Remove the plug which you inserted into the rear of the transmission housing.
- Insert the yoke into the transmission housing and onto the transmission output shaft. Make sure that the yoke assembly does not bottom on the output shaft with excessive force.
- Locate the marks which you made on the rear driveshaft yoke and the pinion flange prior to removal of the driveshaft assembly. Install the driveshaft assembly with the marks properly aligned.
- Install the U-bolts and nuts that attach the universal joint to the pinion flange. Tighten the U-bolt nuts to 15 ft. lbs.