Remove Pinion And Bearing Cage Assembly
Start By:
a. remove differential carrier
1. Remove the cotter pin, hold drive shaft flange stationary and remove pinion shaft nut and washer from center of flange.
| NOTICE |
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Do not attempt to drive the flange off pinion shaft, or damage/distortion may occur to flange or shaft. |
2. Remove the drive shaft flange (1) with a suitable puller (2).
3. Remove the pinion cage and bearing cover bolts (3).
4. Remove bearing cover assembly (4).
| NOTICE |
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Only use the puller holes to remove bearing cage and pinion. The use of a pinch bar will damage the shims, and driving the pinion from inner end with a drift will damage the bearing lock ring groove. |
5. Remove cage assembly (5) by installing bolts (6) in the three threaded puller holes. Tighten bolts alternately and evenly in small increments.
6. Remove and wire the shim pack together to maintain the same adjustment at assembly.
Install Pinion And Bearing Cage Assembly
Pinion Cage Shim Adjustment (With Pinion Setting Gauge)
NOTE: The correct use of a pinion setting gauge will simplify the accurate installation of the pinion and cage assembly into the carrier. When using the pinion setting gauge, never use the nominal pinion mounting dimension without first modifying it to a workable value.
- 1. The nominal pinion mounting dimension (2) indicates the proper distance from centerline (5) of the ring gear (7) to front bearing shoulder (1) of the pinion gear (6).
- 2. However, because the pinion setting gauge measures the distance from the ring gear centerline (5) to the rear bearing shoulder (4) at the nose of the pinion rather than at the front bearing shoulder (1), it becomes necessary to subtract the length of the pinion head and rear bearing from the nominal pinion mounting dimension in order to establish the correct nominal gauge dimension to work with.
- 3. To accurately install and adjust the straddle mounted pinion and cage assembly in a typical single reduction carrier using a pinion setting gauge, follow these procedures:
- 2. However, because the pinion setting gauge measures the distance from the ring gear centerline (5) to the rear bearing shoulder (4) at the nose of the pinion rather than at the front bearing shoulder (1), it becomes necessary to subtract the length of the pinion head and rear bearing from the nominal pinion mounting dimension in order to establish the correct nominal gauge dimension to work with.
NOTE: All dimensions given in examples that follow are in inches since the numbers stamped on gear sets designate thousandths of an inch.
a. Record the nominal pinion mounting dimension (2) and the original shim pack thickness for future reference.
b. With a micrometer or vernier scale, measure the length (3) of the pinion gear and rear bearing from pinion front shoulder (1) to shoulder of rear bearing (4). Mark the spot on the bearing from which this measurement was taken. Later, when using the pinion setting gauge, clamp step plate to this same spot for consistency in the calculations.
c. Subtract the measured pinion gear and bearing length from the nominal pinion mounting dimension (2) to establish the pinion nominal gauge dimension (X).
Example:
The remainder (4.809) is the basic value or nominal gauge dimension for using the pinion setting gauge.
NOTE: See the topic Gear Set Identification for location of pinion cone (PC) variation number.
d. Modify nominal gauge dimension (4.809) by the pinion cone (PC) variation number etched on pinion (i.e. PC +3 or PC -5). This PC variation number indicates the variation (in thousandths of an inch) from the nominal mounting distance of that specific gear set. As indicated by its sign, add or subtract this value from the nominal gauge dimension that was established in step 3. This will give the corrected pinion gauge dimension.
Example: PC = +3
4.809 + .003 = 4.812 inch
Example: PC = -5
4.809 - .005 = 4.804 inch
e. Install the pinion and cage assembly into the carrier, using the original shim pack that was removed when unit was disassembled. Tighten all pinion cage bolts to the specified torque.
f. Assemble step plate (11) to end of pinion bearing (10) and position the pinion setting gauge assembly into the differential bearing bores using the proper adapter discs (9). Adjust the arbor so micrometer (8) is directly over and at a 90° angle to the step plate.
g. Run the micrometer down to measure the distance to the step plate. Make note of this measurement and use the procedures that follow to calculate the correct shim pack thickness.
NOTE: Subtract step plate thickness (.400 in) from the corrected pinion gauge dimension calculated in step d.
Example:
| NOTICE |
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Use a minimum of three shims per pack. If pack is made up from various thicknesses of shims, locate the thinnest shims on both sides of the pack to get maximum sealing ability. |
4. After making any necessary corrections to the shim pack, install the pinion and bearing cage assembly (with shim pack installed) into the carrier and tap into position with soft mallet.
5. Install and tighten the bolts to the specified torque.
6. Recheck the micrometer measurement again to be certain of the correct pinion adjustment. Go to step 7 at end of Pinion Cage Shim Adjustment (Without Pinion Setting Gauge).
Pinion Cage Shim Adjustment (Without Pinion Setting Gauge)
A second means of accurately installing a new pinion and cage assembly into the carrier is to mathematically calculate the proper pinion cage shim pack thickness. Use the procedure that follows:
1. Measure the thickness of the original shim pack used with the gear set being replaced. Use a micrometer or vernier gauge. Record this measurement for future use.
NOTE: See the topic Gear Set Identification for location of pinion cone (PC) variation number.
2. Observe the pinion cone (PC) variation number on the original pinion being replaced. If this number is a plus (+) value, subtract it from the original shim pack measurement recorded in step 1. If the PC number is a minus (-) value, add it to the measurement from step 1. Make a note of this value.
NOTE: The value calculated from step 2 will establish a standard shim pack thickness, without a variation. This value will be used in calculating the shim pack thickness used with a new pinion and gear set.
3. Observe the PC variation number on the new pinion. Add or subtract this number as indicated by the variation sign, (+) add or (-) subtract, from the calculated standard shim pack thickness in step 2.
The resulting answer indicates the thickness (in thousandths of an inch) of the new shim pack to be used.
NOTE: All dimensions given in the example that follows are in inches since numbers stamped on gear sets designate thousandths of an inch.
Example Of Calculation:
| NOTICE |
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Use a minimum of three shims per pack. If pack is made up from various thicknesses of shims, locate the thinnest shims on both sides of the pack to get maximum sealing ability. |
4. Position the corrected shim pack on cage assembly (5) between cage and carrier (7).
5. Install the pinion and bearing cage assembly (with shim pack installed) into the carrier and tap into position with soft mallet.
6. Install bolts (3) and tighten bolts to the correct torque.
7. After installing the pinion and cage assembly into carrier, make a gear tooth contact check. See Install Differential and Ring Gear Assembly.
End By:
a. install differential carrier
Disassemble Pinion And Bearing Cage Assembly
Start By:
a. remove pinion and cage assembly.
1. Tap the pinion shaft out of cage with a soft mallet or press shaft from cage.
2. Remove the outer bearing from cage.
3. Remove the spacer or spacer combination from pinion shaft.
4. If necessary to replace rear thrust bearing (1) or radial bearing, remove with press or suitable puller.
5. Remove the oil seal assembly from inside the bearing cover.
Assemble Pinion And Bearing Cage Assembly
1. If new bearing cups are to be installed, press the cups into pinion bearing cage until firmly against the cage shoulders.
2. Lubricate bearings and cups with the recommended axle lubricant.
3. Press rear thrust bearing cone (2) and radial bearings (1) firmly against the shoulders of pinion (3) with a suitable sleeve that will bear only on the inner race of bearings.
4. Install radial bearing lock ring and squeeze the ring into the pinion shaft groove with a pliers.
| NOTICE |
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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. |
5. Insert the pinion and bearing assembly into the pinion cage, and position the spacer or spacer combination over the pinion shaft.
6. Press the front bearing firmly against spacer.
7. Rotate the pinion cage several revolutions to be sure there is normal bearing contact. The rotating torque must now be checked to determine if spacers used give the correct pinion bearing preload.
Checking Pinion Bearing Preload
NOTE: If a press is not available, the preload may be checked with pinion nut tightened to a torque of 955 to 1230 Nm (700 to 900 lb ft).
A. Check bearing preload torque while under a press load (4) of 237 600 N (54 000 lbs). Wrap a soft wire or cord around cage (5), attach a spring scale (6) and pull straight out at a steady rate. Use only the rotating torque rate of pull, not starting torque.
Rotating torque is calculated by the pull force (spring scale reading) × the bearing cage radius. If the unit of measurement has to be changed, then the calculated torque must be divided by the correct unit of measurement (i.e. Torque in units of pound feet = pounds pull × inches of bearing cage radius divided by 12 inches).
Example (English Units):
Bearing cage diameter = 6 inches
Scale reading = 4 pounds
Radius = 6 divided by 2 = 3 inches
Rotating torque = 4 lb × 3 in = 12 lb in
If the unit of measurement for rotating torque needs to be changed to pound feet:
12 lb in divided by 12 in = 1 lb ft
NOTE: If rotating torque is not within 0.56 to 1.70 Nm (5 to 15 lb in), use a thinner spacer to increase preload torque or a thicker spacer to decrease preload torque.
B. Press flange against forward bearing and install washer and pinion shaft nut.
C. Place pinion and cage assembly over carrier studs, hold flange and tighten pinion shaft nut to 955 to 1230 Nm (700 to 900 lb ft). The flange must be held with a suitable tool or fixture to tighten the pinion shaft nut.
D. Recheck the pinion bearing preload torque. If the rotating torque now is not within 0.56 to 1.70 Nm (5 to 15 lb in), repeat the foregoing procedure.
8. Hold the flange stationary and remove pinion shaft nut and flange.
9. Lubricate the pinion shaft oil seal (9) and cover outer edge of seal body with a sealing compound (non-hardening). Press the seal against the shoulder of bearing cover (7) with a seal driver (8).
10. Install a new gasket and bearing cover (7) on bearing cage (5) and align the holes.
11. Press flange (10) against the forward bearing and install washer and pinion shaft nut.
12. Hold flange stationary and tighten the pinion shaft nut 955 to 1230 Nm (700 to 900 lb ft).
End By:
a. install pinion and cage assembly