See Figures 1 through 5
The Auburn limited slip differential case is non-serviceable and must be replaced as an assembly. Removal and replacement of the limited slip differential case and service on the side bearings and ring gear is the same as for the standard rear axle.
STANDARD REAR AXLE
Before disassembly, there are some things to check. First drain the oil and examine it. If there is heavy gear or bearing wear in the axle, usually the oil takes on a metal-flake appearance from the worn metal being suspended in the oil. Also check the backlash, described later in this procedure. This information can be useful in determining the cause of axle problems and in deciding on the shim packs to be used for assembly.
- With the axle properly supported and the brake drums removed, remove the rear cover.
- Remove the pinion shaft lock bolt, pinion shaft and C locks from the button end of the axle shaft.
- Remove the axle shafts and carefully pry out the oil seal from each end of the housing.
- Use the bearing removal tools to remove the axle be.
- Make sure the tool engages the outer race of the bearing.
- Roll the pinion gears out of the case with their thrust washers. Label their position.
- Remove the side gears and thrust washers and label their position.
- Mark the differential bearing caps left and right and remove them.
- Insert a pry bar into the differential window and carefully pry the differential out of the axle housing. Be careful not to damage the gasket surface of the housing.
- When removing the differential bearing races, keep the shims and spacers together with the race and label them left and right.
- Install the puller on the differential side bearing, making sure the jaws contact the inner race of the bearing, not the cage. Remove the bearings.
- Remove the ring gear from the differential case, using a brass drift and hammer. The 10 bolts are left hand thread. DO NOT pry the gear off, this will damage the gear and the case.
- Before removing the drive pinion, use an inch pound torque wrench to see how much torque is required to turn the pinion. This checks the bearing preload.
- Install the pinion flange holding tool remove the pinion flange nut.
- To remove the pinion flange use the special puller.
- To remove the drive pinion, put the rear housing cover on with 2 screws so the pinion doesn't fall to the floor.
- Put the flange nut onto the pinion a few thread and use a hammer and soft drift pin to drive the pinion out of the housing.
- With the pinion out, remove the collapsible spacer.
- Remove the oil seal and outer pinion bearing.
- To remove the inner pinion bearing, use the bearing pulling tool J-25320 and a press. Keep track of the shims under the bearing. If equipped with anti-lock brakes, remove the rear speed sensor ring using puller tool J-22912-01.
- Remove the pinion drive bearing races from the case with a hammer and brass drift pin.
Clean all parts in a clean solvent and dry with air. Carefully inspect the housing for damage to the sealing areas and the bearing areas for burrs or nicks that may interfere with assembly. Remove any imperfections that are found. Thoroughly clean the housing using solvent, not steam or water. Any metal chips or rust left in the housing will damage the gears and bearings. Check the housing for cracks.
Check the differential gears, shafts and thrust washers for uneven or heavy wear patterns. Check the differential case for cracks and signs of heat damage or scoring. Check the fit of the gears on the axle shafts and in the differential case. If in doubt, replace the parts.
Inspect the pinion shaft splines for wear and check the fit with the pinion flange. If the sealing surface on the flange is nicked or worn, replace the flange. Compare the wear patterns on the ring and pinion gears for excessive wear or signs of heat damage. A ring and pinion gear are a matched set and must be replaced together.
Inspect the bearings for signs of heat damage or contamination. The big end of tapered rollers is where signs of wear or damage will appear first. Low mileage units will show some scratches on the bearings from initial preload. If the (oiled) bearing still feels smooth, it need not be replaced. If the axle was used for an extended period with very loose bearings, the ring and pinion should be replaced. When replacing bearings, also replace the outer race.Assembly
Several special assembly tools are required for correct measurement and positioning of the ring and pinion.PINION DEPTH ADJUSTMENT
- Clean all gage parts.
- Lubricate the front and rear pinion bearings with gear oil.
- With the outer races installed into the axle housing, place the bearings into the outer races and secure them in place with the pilot washers and stud assembly tool and gage plate as shown.
- Torque the J-21777-43 stud assembly to 20 inch lbs. (2.2 Nm).
- Rotate the gage plate and bearings several revolutions to seat the bearings.
- Torque the stud assembly.
- Install the arbor, side bearing disks and dial indicator as shown.
- Install the side bearing caps and finger tighten the bolts.
- Rotate the gage plate until the gaging areas are parallel with the disks.
- Position the gage plate shaft assembly in the carrier so that the dial indicator rod is centered on the gage area of the gage block.
- Set the dial indicator at zero and preload the dial to about 3 / 4 turn of the needle.
- Rotate the gage shaft to find the high point and zero the dial.
- Rotate the gage shaft until the dial indicator rod does not touch the gage block.
- Record the actual number on the dial indicator, not the number which represents how far the needle traveled. This is the nominal pinion setting. Example: If the indicator moved left 0.067 inch (1.7mm) to a reading of 0.033 inch (0.84mm), record the reading of 0.033 inch (0.84mm), not the travel of 0.067 inch (1.7mm). At this point the indicator should be in the 0.020-0.050 inch (0.050-1.27mm) range.
- Check the pinion face for a pinion adjustment mark. This mark is the best running position for the pinion from the nominal setting.
- Remove the measuring tools and install the pinion shim according to the measurements taken.
- Lubricate all parts with gear oil.
- Install the side gear thrust washers to the side gears.
- Install the side gears into the same side that they were removed from.
- Install the pinion gears without the thrust washers. To do this, place one pinion gear onto the side gears and rotate the side gears until the pinion is opposite the differential window. Install the second pinion gear so the pinion holes line up and rotate the gears into place in the differential housing.
- Install the pinion gear thrust washers by rotating the pinion gears just enough to slide the washer into place.
- Install the pinion shaft and pinion shaft screw.
- Install the ring gear to the differential case by putting two studs into the ring gear on opposite sides. Place the gear onto the case and align the holes with the studs.
- Use new bolts to secure the ring gear. Tighten each one in stages, gradually pulling the gear into place. When the gear is fully seated, torque the bolts in 2 or 3 steps to 90 ft. lbs. (120 Nm).
- Install the differential side bearings using the proper tools. Support the differential when driving the bearing on the opposite side so the bearing does not take the load.
The adjustment is to position the differential properly side-to-side in the axle housing so the bearing are properly loaded. This is done by changing the shim thickness on both sides equally so the original backlash is maintained. Productions shims are made of case iron and must not be reused. Measure the shims and spacers one at a time and add the numbers to obtain the original shim thickness. The new service spacer thickness is 0.170 inch (4.32mm). The shims are available in increments of 0.004 inch (0.10mm) in sizes from 0.040-0.100 inch (1.0-2.5mm)
- With the bearing races installed and lubricated, set the differential case into the axle housing to set the side bearing pre-load adjustment.
- Insert the gaging tool between the axle housing and the left bearing cup.
- Move the tool back and forth in the bore while turning the adjusting nut to the right until a noticeable drag is produced. Tighten the lock bolt on the side of the tool and leave the tool in place.
- Install a new spacer and a shim between the right bearing race and the axle housing.
- Determine the bearing preload by inserting progressively larger feeler gages between the carrier and the shim. Push the gage down so it contacts the shim at the top and bottom, then contacts the axle housing. The point just before additional drag begins is the correct feeler gage thickness. This is the zero setting without preload.
- Remove the gaging tool, spacer, shim, feeler gage and differential from the axle housing.
- Measure the gaging tool in 3 places using a micrometer and average the readings.
- Add the dimensions of the right side spacer, shim and feeler gage.
- For an initial backlash setting, move the ring gear away from the pinion by subtracting 0.010 in. (0.04mm) from the ring gear side of the shim pack and adding the same to the opposite side.
- To obtain the proper preload on the side bearings, add 0.010 inch (0.04mm) to the measurement of each shim pack.
- The differential is ready for installation.
- The bearing races should already be installed from the pinion depth adjustment done earlier. Install the pinion inner bearing onto the pinion; drive the inner race until it is seated on the shims.
- Install a new collapsible spacer.
- Install the pinion into the axle housing.
- While holding the pinion in place, carefully drive the outer bearing onto the pinion shaft.
- Install a new pinion oil seal.
- Install the pinion flange by tapping it with a soft mallet until enough threads show to start the nut.
- Install the flange holding tool and install the washer and a new nut. DO NOT tighten the nut. The bearing preload must be adjusted.
- Tighten the pinion nut just until the end play is taken out.
- Remove the holding tool and use an inch pound torque wrench to determine how much torque is required to turn the pinion. This is bearing preload. Some of the resistance to turning the pinion shaft comes from the seal, so make sure it is properly lubricated. Turn the pinion several times to seat the bearings before taking a reading.
- The preload should be 20-25 inch lbs. (2.3-2.8 Nm) on new bearings. On used bearings the preload should be 10-15 inch lbs. (1.1-1.7 Nm).
- If the preload is low, tighten the nut in small increments and check the preload again. If the preload is exceeded, the collapsible spacer must be replaced.
- Once the preload is correct, install the differential and set the backlash.
- With the side bearing preload properly adjusted and the differential installed, install the bearing caps and torque the bolts to 55 ft. lbs. (75 Nm). Rotate the pinion and differential several times to seat the bearings.
- Install a dial indicator to the axle housing. A unit with a magnetic base is acceptable.
- Touch the stem to the heel of a tooth on the ring gear. That's the outer edge of the convex or drive side.
- Hold the pinion fast and rock the ring gear to see how much play there is between the gear teeth; backlash. Record the reading and check 3 or 4 more places.
- The readings should all be within 0.002 in. (0.05mm). If the readings vary more than this, check for burrs, a distorted case flange or uneven torque of the ring gear bolts.
- The correct backlash is 0.005-0.009 in. (0.13-0.23mm) for new gear sets.
- To adjust backlash, remove shim thickness from one side of the differential and add the same amount to the other side. This moves the ring gear to one side while maintaining the side bearing preload. Moving 0.002 inch (0.05mm) of shim changes the backlash by 0.001 inch (0.03mm).
- When the backlash is correctly adjusted, remove the side bearing caps and shim packs.
- Add 0.004 inch (0.10mm) of shim to the right side shim pack and drive the shim pack into place. Install the bearing cap and torque the bolts to 55 ft. lbs. (75 Nm).
- Add 0.004 inch (0.10mm) of shim to the right side shim pack and install it. Install the left bearing cap but do not tighten the bolts yet.
- Recheck the backlash and adjust as needed.
- Install new axle bearings and oil them with gear oil.
- Install new axle seals and oil the lips with gear oil.
- Install the axle shafts and engage the splines with the side gears in the differential.
- Install the C locks on the end of the shafts. Pull out on the shafts to seat the C locks in the side gears.
- Install the pinion shaft into the differential gears and install the lock bolt. DO NOT over tighten the lock bolt. Torque it to 25 ft. lbs. (34 Nm).
- Install the rear cover with a new gasket and torque the bolts to 20 ft. lbs. (27 Nm). Refill with lubricant.