REMOVAL & INSTALLATION
See Figures 1, 2, 3 and 4
The following procedure can be used on all years and models. Slight variations may occur but the basic procedure should cover all years and models.Special tools and mechanical skill are needed for this job.1968-87 Models
- Raise and support the vehicle. Remove the rear wheels and brake drums, or calipers.
- Mark the driveshaft and yoke for reassembly and disconnect the driveshaft from the rear yoke.
- With a socket on the pinion nut and an inch lb. torque wrench, rotate the drive pinion several revolutions. Check and record the torque required to turn the drive pinion.
- Remove the pinion nut. Use a flange holding tool to hold the flange while removing the pinion nut. Discard the pinion nut.
- Mark the yoke and the drive pinion shaft for reassembly reference.
- Remove the rear yoke with a puller.
- Inspect the seal surface of the yoke and replace it with a new one if the seal surface is pitted, grooved, or otherwise damaged.
- Remove the pinion oil seal using tools 1175-AC and T50T-100A or equivalent.
- Before installing the new seal, coat the lip of the seal with rear axle lubricant.
- Install the seal, driving it into place with a seal driver.
- Install the yoke on the pinion shaft. Align the marks made on the pinion shaft and yoke during disassembly.
- Install a new pinion nut. Tighten the nut until end-play is removed from the pinion bearing. Do not overtighten.
- Check the torque required to turn the drive pinion. The pinion must be turned several revolutions to obtain an accurate reading.
- Tighten the pinion nut to obtain the torque reading observed during disassembly (Step 3) plus 5 inch lbs. Tighten the nut slightly each time, to avoid overtightening. Do not loosen and then retighten the nut. Pinion preload should be 8-14 inch lbs. (0.8-1.5 Nm).
If the desired torque is exceeded a new collapsible pinion spacer sleeve must be installed and the pinion gear preload reset.
- Install the driveshaft, aligning the index marks made during disassembly. Install the rear brake drums, or calipers, and wheels.
- Raise and safely support the vehicle. Matchmark the rear driveshaft yoke and the companion flange so they may be reassembled in the same way to maintain balance.
- Disconnect the driveshaft from the rear axle companion flange, remove the driveshaft and remove the driveshaft from the extension housing. Plug the extension housing to prevent leakage.
- Measure the ring gear axle to determine whether it is a 7.5 in. (190mm) or 8.8 in. (223mm) rear gear axle.
- Install an inch pound torque wrench on the pinion nut and record the torque required to maintain rotation of the pinion through several revolutions.
- While holding the companion flange with tool No. T78P-4851-A or equivalent, remove the pinion nut.
- Clean the area around the oil seal and place a pan under the seal.
- Mark the companion flange in relation to the pinion shaft so the flange can be installed in the same position.
- Remove the rear axle companion flange using tool No. T65L-4851-B or equivalent.
- Pry the seal out of the housing using a prybar.
- Clean the oil seal seat surface and install the seal in the carrier using seal replacer tool No. T79P-4676-A or equivalent. Apply lubricant to the lips of the seal.
- Apply a small amount of lubricant to the companion flange splines, align the marks on the flange and and the pinion shaft and install the flange.
- Install a new nut on the pinion shaft and apply lubricant on the washer side of the nut.
- Hold the flange with the holder tool while tightening the nut. Rotate the pinion to ensure proper seating and take frequent pinion bearing torque preload readings until the original recorded preload reading is obtained.
- Based on the factory torque specification of 170 ft. lbs. (230 Nm) for the 7.5 in. (190mm ) rear gear axle, and 140 ft. lbs. (190 Nm) for the 8.8 in. (223mm) rear axle nut, adjust the preload obtained earlier. If the preload obtained earlier is less than the specification, then tighten until the correct preload is reached. If the preload obtained earlier is more than the specification, then loosen the pinion until the desired preload is reached.
If reduced preload is required, a new collapsible pinion spacer and pinion nut should be installed.
- Remove the plug from the transmission extension housing and install the front end of the driveshaft on the transmission output shaft.
- Connect the rear end of the driveshaft to the axle companion flange, aligning the scribe marks and tighten the 4 bolts to 71-95 ft. lbs. (95-130 Nm).
- Add lubricant to the axle until it is 1 / 4 - 9 / 16 in. (6-14mm) below the bottom of the fill hole with the axle in operating position.
- Make sure the axle vent is not plugged with debris.