Remove Differential Case And Ring Gear Assembly
Start By:
a. remove differential carrier
1. Place the carrier in suitable holding fixture.
NOTE: If the initial inspection indicates that the drive gear is not going to be replaced, the established backlash should be measured and recorded for use at assembly.
2. Loosen jam nut and back off thrust adjusting screw (1).
3. Center punch mark differential carrier leg and bearing cap on one side to identify at assembly.
4. Remove both adjusting nut locks (2).
5. Remove bearing cap bolts (3), bearing caps (4) and adjusting nuts (5).
6. Lift differential and gear assembly (6) out of the carrier (7).
Install Differential And Ring Gear Assembly
1. Temporarily install the bearing cups (1), threaded adjusting rings (2) and bearing caps (3). Tighten bearing cap bolts to the proper torque.
2. Bearing cups (1) must be of a hand push fit in the bores. If necessary, rework the bores with a scraper or emery cloth until a hand push fit is obtained. Use a blued bearing cup as a gauge to check the fits as work progresses. Once the cups fit properly, remove bearing caps (3).
3. After checking all related parts, lubricate bearings and cups with the recommended axle lubricant.
4. Place the bearing cups over the assembled differential bearing cones, and position the differential assembly (4) in the carrier (5).
5. Insert bearing adjusting nuts (6) and tighten by hand against the bearing cups.
| NOTICE |
|---|
If bearing caps do not position properly, adjusting nuts may be cross threaded. Do not force the caps, because forcing caps into position will result in irreparable damage to the carrier housing or bearing caps. Remove the caps and reposition the adjusting nuts. |
6. Install bearing caps (3) in the correct location as marked, and tap lightly into position.
7. Install flatwashers (where used) and bearing cap bolts, and tighten to correct torque.
8. At this time, the differential bearing preload, ring gear backlash, gear tooth contact and thrust screw must be checked and adjustments made using the following procedures:
Adjusting Differential Bearing Preload
A. Using a dial indicator at back face (7) of ring gear as shown, loosen the bearing adjusting nut (6) on side opposite ring gear just enough to indicate some end play on the dial indicator.
B. Now tighten the same adjusting nut enough to obtain zero end play.
C. Check the ring gear for runout. If the runout exceeds 0.20 mm (.008 in), remove the differential assembly and determine cause.
D. To preload differential bearings, tighten each adjusting nut one notch from zero end play.
Checking Ring Gear Backlash
NOTE: If the ring gear has not been replaced, use the original backlash that was recorded befoe disassembly.
A. Install the dial indicator (8) as shown. Backlash for new gears should be initially set at 0.25 mm (.010 in).
B. Set backlash by making adjustment to the ring gear only. This is done by backing off adjusting nut of one side, then tightening the opposite nut by the same amount. Make the changes in one notch increments, and recheck the dial indicator after each change.
Checking Gear Tooth Contact
NOTE: Coating applied to approximately twelve teeth is sufficient for checking purposes.
A. Apply oiled red lead lightly to the ring gear teeth with a brush. When pinion is rotated, the red lead is squeezed away by the contact between teeth of pinion and ring gear. This leaves bare areas of the exact size, shape and location of the tooth contact points.
NOTE: Sharper impressions may be obtained by applying a small amount of resistance to the gear with a flat steel bar, while at the same time rotating the pinion with a wrench.
B. For determining if adjustment is necessary, check the drive side of gear teeth. Coast side should automatically be correct when drive side is correct.
(a) A high contact pattern indicates pinion is too far away from ring gear. Set the pinion to the correct depth by removing shims from between the pinion cage and carrier. A slight outward movement of the ring gear may also be necessary to maintain correct backlash.
(b) A low contact pattern indicates pinion is too close to ring gear. Set the pinion to the correct depth by adding shims between pinion cage and carrier. Slight inward movement of the ring gear may also be necessary to maintain correct backlash.
NOTE: A high backlash setting can be used to keep the contact from starting too close to the tooth toe (9), and a low backlash setting can be used to keep the contact from starting too far away from the toe.
C. After obtaining a satisfactory tooth contact pattern (especially in relation to the top and bottom of the tooth), the backlash can be altered within the limits of 0.13 mm (.005 in) to obtain a better contact position relative to the length of the tooth.
(a) With adjustments properly made, pinion at correct depth and backlash set at 0.25 mm (.010 in), the hand rolled contact pattern (gears unloaded) will be as shown. The area of contact favors the toe and is centered between the top and bottom of the tooth.
(b) The hand rolled pattern (gears unloaded) shown in previous illustration will now result in a pattern centered in the length of the tooth (as shown above) when the gears are under load. The loaded pattern will be almost full length and the top of pattern will approach the top of the gear tooth.
NOTE: The pattern width on the coast side of the teeth will appear the same as the drive side shown above, but the overall length will now be centered between the toe and heel of gear tooth.
D. After the correct tooth contact pattern has been established, install the adjusting nut locks and bolts.
NOTE: A used ring gear must be set to match existing tooth contact wear pattern. Hand rolled patterns of used gears will be smaller in area and should be located at the toe end of wear pattern.
Thrust Screw Adjustment
A. Remove carrier from stand and position with teeth of ring gear facing downward.
B. Thread the thrust screw (10) in until it is against back face (7) of ring gear.
C. To make the correct adjustment of 0.25 to 0.38 mm (.010 to .015 in) clearance, loosen thrust screw 1/4 turn and tighten jam nut.
D. Recheck adjustment position with a feeler gauge to assure minimum clearance of 0.25 mm (.010 in) during one full rotation of the ring gear.
End By:
a. install differential carrier
Disassemble Differential Case And Ring Gear Assembly
Start By:
a. remove differential case and ring gear assembly
1. If original identification marks are not clear, mark differential case halves (1) with a punch or chisel for correct alignment at assembly.
2. Remove the bolts (2) and separate the differential case halves.
3. Remove side gears (6), spider (5), pinions (3) and thrust washers (4).
| NOTICE |
|---|
Do not use a chisel to remove rivet heads, or damage to gear or case holes may result. |
4. If necessary to separate ring gear (7) from case half (1), remove rivets as follows:
a. Carefully center punch rivets in center of head.
b. Use a drill 0.8 mm (.03 in) smaller than body of rivet and drill through rivet head.
c. Press the rivets out.
5. Remove differential bearings (8) with a suitable puller or a press.
Assemble Differential Case And Ring Gear Assembly
| NOTICE |
|---|
If a new gear set (drive pinion and ring gear) is being installed into the carrier, reference must be made to the topics Gear Set Identification and Adjusting Pinion Cage Shim Pack Thickness (With or Without Pinion Setting Gauge) before proceeding further with the assembly. However, if the original gear set is to be reinstalled, continue on through the following steps. The ring gear must be heated before assembling onto the case half. Excessive metal particles may lodge between the gear and case if gear is pressed or driven onto the case, resulting in gear runout or damage to the case half. |
1. Heat the ring gear in water to approximately 71° to 83° C (160° to 180° F) for about ten minutes before assembly. This provides an easier fit of the gear over the differential case pilot, without he use of a press and without damaging the case and ring gear mating surfaces.
2. Install the bolts/nuts and tighten alternately in even increments until final torque is reached.
3. Use a 0.08 mm (.003 in) feeler gauge (1) to check for maximum gap between back face of ring gear (3) and flange of case half (4). Check at four equally spaced locations around the assembly. If gauge can be inserted more than one half the distance (2), the gear must be removed again. Determine cause, correct and reassemble gear onto case half, again using the procedures in steps 1 and 2.
4. Place the ring gear and case half assembly on a bench with the gear teeth facing upwards.
5. Lubricate differential case inner walls and all components parts with axle lubricant.
6. Position first thrust washer (5) and side gear (6) in the ring gear and case half assembly.
7. Place all four pinion gears (10) and thrust washers (11) in position on spider (7), and install on top of side gear (6) in ring gear and case half assembly.
8. Install second side gear (8) and thrust washer (9) on top of the spider assembly.
NOTE: If Dri-Loc bolts are used, refer to Dri-Loc Procedures at end of this module.
9. Align mating marks, and position case half (12) over the spider assembly and side gear onto the ring gear and case half assembly. Install four bolts equally spaced and draw the assembly together.
10. Check the assembly for free rotation of the differential gears and correct if necessary.
11. Install the remaining bolts and tighten to the correct torque.
12. If the bearings were removed, press the bearings (13) squarely and firmly on each end of the differential case halves.
Checking Rolling Resistance Of Differential Nest
A. Make a checking tool (14) as shown by cutting an axle shaft (from splined end) to an appropriate length, and then welding a nut on the end to accept a wrench socket.
| NOTICE |
|---|
Use soft metal covers over the vise jaws to protect the ring gear, or teeth may be damaged. |
B. Place differential and ring gear assembly in a vise.
C. Insert checking tool (14) into the differential nest inside differential and ring gear assembly. Allow the spline of the checking tool to engage with spline of one side gear (8) only.
D. Using a socket and torque wrench, rotate the differential nest while observing the scale on the torque wrench. The maximum allowable rolling resistance of the differential assembly is 68 Nm (50 lb ft) of torque applied to the one side gear.
E. If torque reading exceeds the specification, the halves will have to be disassembled again to determine the cause.
End By:
a. install differential case and ring gear assembly