FRONT AXLE
FRONT AXLE REMOVAL
FRONT AXLE INSTALLATION
FRONT AXLE ADJUSTMENTS
FRONT AXLE SPECIFICATIONS
FRONT AXLE REMOVAL
(1) Place transmission in netural.
(2) Raise and support the vehicle.
(3) Remove tire and wheel assemblies.
(4) Remove axle half shafts.
(5) Remove exhaust crossover.
(6) Mark front propeller shaft and remove shaft.
(7) Remove suspension crossmember mounting bolts and remove crossmember.
(8) Support axle with hydraulic jack.
(9) Remove axle housing pinion mounting bolts.
(10) Remove axle shaft tube mounting bolts.
(11) Remove differential housing mounting bolts.
(12) Lower axle from the vehicle.
FRONT AXLE INSTALLATION
(1) Raise axle into position.
(2) Install axle mounting bolts and tighten nuts to 95 N·m (70 ft. lbs.).
(3) Install suspension crossmember and bolts. Tighten crossmember nuts to 102 N·m (75 ft. lbs.).
(4) Install front propeller shaft with reference marks aligned and tighten bolts to 115 N·m (85 ft. lbs.).
(5) Install exhaust crossover.
(6) Install axle half shafts.
(7) Check the differential fluid level and add fluid if necessary.
(8) Install tire and wheel assemblies.
(9) Remove support lower the vehicle.
FRONT AXLE ADJUSTMENTS
Ring gear and pinion are supplied as matched sets only. The identifying numbers for the ring gear and side of the ring gear. A plus (+) number, minus (–) number or zero (0) along with the gear set sequence number (01 to 99) is on each gear. This first number is the amount (in thousandths of an inch) the depth varies from the standard depth setting of a pinion marked with a (0). The next two numbers are the sequence number of the gear set. The standard setting from the center line of the ring gear to the back face of the pinion is 99.690 mm (3.925 in.). The standard depth provides the best teeth contact pattern.
Compensation for pinion depth variance is achieved with select shims. The shims are placed gear head.M If a new gear set is being installed, note the depth variance marked on both the original and replacement pinion. Add or subtract the thickness of the original depth shims to compensate for the difference in the depth variances. Refer to the Pinion Gear Depth Variance charts. Note where Old and New Pinion Marking columns intersect. Intersecting figure represents plus or minus amount needed.
Note the painted number on the shaft of the drive pinion (–1, –2, 0, +1, +2, etc.). The numbers represent thousands of an inch deviation from the standard. If the number is negative, add that value to the required thickness of the depth shim(s). If the number is positive, subtract that value from the thickness of the depth shim(s). If the number is 0 no change is
PINION DEPTH MEASUREMENT AND ADJUSTMENT
Measurements are taken with pinion cups and pinion bearings installed in housing. Take measurements with a Pinion Gauge Set, Pinion Block 8177, Arbor Discs 8541 and Dial Indicator C-3339.
(1) Assemble Pinion Height Block 6739, Pinion Block 8177 and rear pinion bearing onto Screw 6741.
(2) Insert assembled height gauge components, rear bearing and screw into the housing through the pinion bearing cups.
(3) Install front pinion bearing and Cone 6740 onto the screw hand tight.
(4) Place Arbor Discs 8541 on Arbor D-115-3 in position in the housing side bearing cradles (Fig. 9). Install differential bearing caps on arbor discs and tighten cap bolts to specification.
(5) Assemble Dial Indicator C-3339 into Scooter Block D-115-2 and secure set screw.
(6) Place Scooter Block/Dial Indicator in position in the housing so dial probe and scooter block are flush against the surface of the pinion height block. Hold scooter block in place and zero the dial indicator. Tighten dial indicator face lock screw.
(7) Slide the dial indicator probe across the gap between the pinion height block and the arbor bar with the scooter block against the pinion height block. Slide the dial probe to the crest of the arbor
bar and record the highest reading.
(8) Select a shim equal to the dial indicator reading plus the drive pinion gear depth variance number marked on the shaft of the pinion gear using the opposite sign on the variance number. For example, if the depth variance is –2, add +0.002 in. to the dial indicator reading.
DIFFERENTIAL BEARING PRELOAD AND GEAR BACKLASH
Achieved by selective shims inserted between the bearing cup and the housing. The proper shim thickness can be determined using slip-fit Dummy Bearings 8398 in place of the differential side bearings and a Dial Indicator C-3339. Before proceeding with the differential bearing preload and gear backlash measurements, measure the pinion gear depth and prepare the pinion for installation. Establishing proper pinion gear depth is essential to establishing gear backlash and tooth contact patterns.
After the overall shim thickness to take up differential side play is measured, the pinion is installed, and the gear backlash shim thickness is measured. The overall shim thickness is the total of the dial indicator reading, starting point shim thicknesses, and the preload specification added together. The gear backlash measurement determines the thickness of the shim used on the ring gear side of the differential case. Subtract the gear backlash shim thickness from the total overall shim thickness and select that amount for the pinion side of the differential.
SHIM SELECTION
(1) Remove side bearings from differential case.
(2) Install ring gear if necessary, on differential case and tighten bolts to specification.
(3) Install Dummy Bearings 8398 on differential case.
(4) Install differential case in the housing.
(5) Insert Dummy Shims 8107 3.0 mm (0.118 in.) starting point shims between both dummy bearings and the housing.
(6) Install the marked bearing caps in their correct positions. Install and snug the bolts.
(7) Using a dead-blow hammer to seat the differential dummy bearings to each side of the differential housing.
(8) Install Pilot Stud C-3288-B in cover bolt hole below ring gear.
(9) Attach Dial Indicator C-3339 to post and position dial indicator plunger on a flat surface on a ring gear bolt head.
(10) Push and hold differential to the pinion gear side of the housing and zero dial indicator.
(11) Push and hold differential case to the ring gear side and record dial indicator reading.
(12) Add the dial indicator reading to the starting point shim thicknesses to determine the total shim thickness necessary to achieve zero differential end play.
(13) Add 0.2 mm (0.008 in) to the zero end play total. This new total represents the shims needed to preload the new differential case bearings.
(14) Rotate dial indicator out of the way on pilot stud.
(15) Remove differential case, dummy bearings and dummy shims from the housing.
(16) Install the pinion gear in the housing. Install the companion flange and establish the correct pinion rotating torque.
(17) Install differential case and Dummy Bearings in the housing with a single dummy shim on the ring gear side of the axle and tighten retaining cap bolts.
(18) Position the dial indicator plunger on a flat surface between the ring gear bolt heads.
(19) Push and hold differential case toward pinion.
(20) Zero dial indicator face to pointer.
(21) Push and hold differential case to ring gear side of the housing.
(22) Record dial indicator reading.
(23) Subtract 0.05 mm (0.002 in.) from the dial indicator reading to compensate for backlash between ring and pinion gears. Add the resulting measurementto the thickness of the single dummy shim. This is the thickness of shim required to achieve proper backlash.
(24) Subtract the backlash shim thickness from the total preload shim thickness. The remainder is the shim thickness required on the pinion side of the housing.
(25) Rotate dial indicator out of the way on pilot stud.
(26) Remove differential case, dummy bearings and dummy shim from the housing.
(27) Install new side bearing cones and cups on differential case.
(28) Install Spreader W-129-B and Adapter Plates 8142-A on the housing and spread open enough to receive differential case.
CAUTION: Never spread over 0.50 mm (0.020 in). If the housing is over-spread, it could be distorted or damaged.
(29) Place the side bearing shims in the differential housing against the housing shoulder.
(30) Install the differential case in the housing.
(31) Rotate the differential case several times to seat the side bearings.
(32) Position the dial indicator plunger against a ring gear tooth (Fig. 18).
(33) Push and hold ring gear upward while not allowing the pinion gear to rotate.
(34) Zero dial indicator face to pointer.
(35) Push and hold ring gear downward while not allowing the pinion gear to rotate. Dial indicator reading should be between 0.12 mm (0.005 in.) and 0.20 mm (0.008 in.). If backlash is not within specifications transfer the necessary amount of shim thickness from one side of the differential housing to the other.
(36) Verify differential case and ring gear runout by measuring ring to pinion gear backlash at eight locations around the ring gear. Readings should not vary more than 0.05 mm (0.002 in.). If readings vary more than specified, the ring gear or the differential case is defective. After the proper backlash is achieved, perform the Gear Contact Pattern procedure.
GEAR CONTACT PATTERN
Gear tooth contact pattern is used to verify the correct running position of the ring and pinion gears. This will produce low noise and long gear life. Gears which are not positioned properly may be noisy and have shorten gear life.
(1) Wipe clean each tooth of the ring gear.
(2) Apply gear marking compound to all of the ring gear teeth.
(3) Verify bearing cap bolts are torque specification.
(4) Apply the brakes lightly to create at 14 N·m
(10 ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions in each directions.
(6) Read gear tooth contact pattern:
² Gear contact pattern correct. Backlash and pinion depth is correct.
² Ring gear too far away from pinion gear. Decrease backlash by moving the ring closer to the pinion gear.
² Ring gear too close to pinion gear. Increase backlash, by moving the ring away from the
² Ring gear too far away from pinion gear. Decrease backlash, by moving the ring closer to the pinion gear.
² Ring gear too close to pinion gear. Increase backlash, by moving the ring away from the pinion gear.
² Pinion gear set too low. Increase pinion gear height, by increasing the pinion depth shim thickness.
² Pinion gear set too high. Decrease pinion depth, by decreasing the pinion depth shim thickness.
AXLE SPECIFICATIONS
Axle Ratio 3.55, 3.92
Differential Case Flange Runout 0.076 mm (0.003 in.)
Differential Side Gear Clearance 0-0.15 mm (0-0.006 in.)
Ring Gear Diameter 205 mm (8.0 in.)
Ring Gear Backlash 0.12-0.20 mm (0.005-0.008 in.)
Ring Gear Runout 0.12 mm (0.005 in.)
Pinion Bearing Preload - New Bearings 2.0-2.8 N·m (18-25 in. lbs.)
Pinion Bearing Preload - Original Bearings 1-2 N·m (10-20 in. lbs.)
