REMOVAL & INSTALLATION
See Figures 1 through 5
Replacement of the pinion oil seal involves removal and installation of only the pinion nut and the axle end yoke. However, this operation disturbs the pinion bearing preload, and this preload must be carefully reset during assembly.
- Raise the vehicle and support safely on jackstands.
- Remove the rear wheels and tires.
- Scribe alignment marks on the driveshaft end and the axle end yoke to insure proper driveshaft positioning during assembly.
- Place a suitable drip pan below the axle housing to catch any spilled fluid.
- Disconnect the driveshaft from the rear axle end yoke and remove the driveshaft from the transmission extension housing. Cap or plug the transmission extension housing to prevent oil leakage.
- Install an inch pound torque wrench on the pinion nut, then record the torque required to maintain rotation of the pinion gear through several revolutions.
- While holding the end yoke with holding tool T78P-4851-A, or equivalent, remove the pinion nut using a suitable socket on a breaker bar or equivalent. Clean the area around the oil seal and place a drain pan under the yoke to catch any fluid leakage.
- Mark the axle yoke in relation to the pinion shaft so the flange can be installed in the same position.
- Use a suitable puller tool to remove the axle end yoke from the pinion shaft.
- Remove the pinion seal with a small prytool or other suitable tool and discard the seal.
- Check the splines on the pinion shaft to make sure they are free from burrs or any other damage. If burrs are noted, remove them by using a fine crocus cloth, working in a rotational pattern.
- Apply multi-purpose, long-life grease between the lips of the pinion seal.
- Install the seal using seal replacer tool T79P-4676-A or equivalent. Place the seal on the tool, then drive it into position on the pinion.
- Check the seal surface of the yoke for scratches, nicks or a groove around the diameter. If any of these conditions exist, replace the yoke. Apply a small amount of lubricant to the end yoke splines, then align the mark on the end yoke with the mark on the pinion shaft and install the yoke.
The companion shaft must never be hammered on or installed with power tools.
- Wipe the pinion clean.
- Install a new nut and spacer on the pinion shaft, then hold the end yoke and tighten the nut while rotating the pinion occasionally to insure proper bearing seating. In addition, take frequent pinion bearing torque preload readings with the inch pound torque wrench until the original recorded rotational torque reading is obtained or to 8-14 inch lbs. (1-2 Nm).
Under no circumstances should the pinion nut be backed off to reduce preload. If reduced preload is required, a new collapsible pinion spacer and pinion nut must be installed.
- Remove the cap or plug from the extension housing and install the front of the driveshaft on the transmission output shaft. Connect the rear end of the driveshaft to the axle end yoke, aligning the scribe marks made earlier. Tighten the four nuts to 70-95 ft. lbs. (95-128 Nm).
- Install the wheels and tires. Lower the vehicle.
- Remove the filler plug and add hypoid gear lubricant until it is about 1 / 2 in. (13mm) below the bottom of the filler hole in the running position. Install the filler plug and tighten it to 15-30 ft. lbs. (20-41 Nm).