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Home >> Ford Truck >> 1990 >> Bronco Full Size V8-302 5.0L >> Repair and Diagnosis >> Transmission and Drivetrain >> Drive Axles, Bearings and Joints >> Service and Repair >> Disassembly and Assembly >> Differential Case >> Assembly to Carrier >> Pinion and Ring Gear Backlash

Pinion and Ring Gear Backlash

1. Assemble ring gear to differential case. Use new bolts and tighten alternately and evenly to 81-81 Nm (45-60 ft. lb).

2. Place the differential case into position in the carrier. (Master bearings should still be installed.)

3. Force the differential case away from the drive pinion gear, until it is completely seated against the cross bore face of the carrier. Position a dial indicator so the indicator tip rests on a differential case bolt as shown in Fig. 43. Zero the dial indicator.

4. Force ring gear against pinion gear. Rock ring gear slightly to make sure gear teeth are in contact. Then, force ring gear away from drive pinion gear, making sure the dial indicator returns to zero. Repeat this procedure until the dial indicator reading is the same. This reading reveals the amount of shims necessary between the differential case and differential bearing on the ring gear side.

5. Remove the differential case from the carrier and remove the master bearings from the case.

6. As determined in step 4, place the required amount of shims on the ring gear hub of the differential case. For example: if the reading in step 4 was 1.14mm (0.045 inch), place 1.14mm (0.045 inch) amount of shims on the hub of the ring gear side of the differential case.

FIG. 57 Differential Side Bearing Installation:




7. Install the bearing cone on the hub of the ring gear side of the differential case. Drive the bearing onto the hub using Differential Side Bearing Replacer, T8OT-4000-J or equivalent as shown in Fig. 57.

8. To determine the correct amount of shims to be placed on the hub of the drive pinion side of the differential case, subtract the reading obtained in step 4 from the Differential Total Case Endplay. Total Case Endplay was determined in steps 3 and 4 of Differential Total Case Endplay. When this amount is determined, add 0.26mm (0.010 inch) to the amount. This is the required amount of shims to be placed on the hub of the drive pinion side of the differential case.

For example: Total Case Endplay was 2.3Omm (0.091 inch). The reading in step 4 was 1.14mm (0.045 inch), and when subtracted from 2.3Omm (0.091 inch) gives 1.l6rnm (0.046 inch), 0.26mm (0.010 inch) is added to give 1 .42mm (0.056 inch) amount of shims to be placed on the hub of the drive pinion side of the differential case.

9. Place the required amount of shims on the hub of the drive pinion side of the differential case.

10. Install the bearing cone on the hub of the drive pinion side of the differential case. Place Step Plate, D8OL-630-5 or equivalent on the ring gear side bearing to protect the bearing. Drive the bearing onto the hub of the drive pinion side of the differential case using Differential Side Bearing Replacer, T8OT-4000-J (or equivalent).

FIG. 57 Differential Side Bearing Installation:




11. Install bearing cone on the pinion side of the differential case with special Tools T8OT-4000-J or equivalent, Differential Bearing Replacer (Fig. 57). Place the Pinion Bearing Cone Replacer, T53T-4621-C or equivalent, on the ring gear bearing to prevent damage.

12. Install the differential bearing cups on the bearing cones.

13. With the spreader and dial indicator installed on the case, spread the carrier housing but do not exceed 0.25mm (0.015 inch).

14. Install the differential case in the carrier. If necessary use a rawhide or plastic hammer to seat the differential case into the carrier housing cross bore. With partial and non-hunting/partial ring gear and pinion sets, align the marks on the ring gear and drive pinion. Be careful to not nick the teeth of the ring gear or pinion. Remove the spreader and dial indicator from the case.

15. Install bearing caps and bolts. Make sure the letters or numbers stamped on the caps correspond in both position and direction with the letters or numbers stamped into the carrier. Tighten bolts to 108-122 Nm (80-90 ft. lb).

Fig. 58 Ring Gear and Backlash Check:





FIG. 59 Bead Surface:





16. Install dial indicator Tool 4201-C or equivalent on the case as shown in Fig. 58. Check ring gear and pinion backlash at three equally spaced points on

the ring gear. Backlash tolerance is 0.1 3-0.23mm (0.005-0.009 inch) and cannot vary more than 0.08mm (0.003 inch) between the three points. If backlash is high, the ring gear must be moved closer to the pinion, by moving shims to the ring gear side from the opposite side. If backlash is low, the ring gear must be moved away from the pinion by moving shims from the ring gear side to the opposite side.

Fig. 60 Checking Backlash:




17. Obtain a gear tooth contact pattern check, prior to complete reassembly (Fig. 60).

18. Apply a bead 3.175-6.35mm (1/8-1/4 inch) high and 3.175-6.35mm (1/4-1/2 inch) wide of Silicone Rubber sealant, D6AZ-19562-A (clear) or -BA (black) (ESB-M4G92-A and ESE-M4G195-A) or equivalent on the mating surfaces of the carrier mounting face support arm as shown in Fig. 59.

Allow one hour curing time after the axle carrier Is assembled to the axle arm before Installing lubricant and operating vehicle.

19. Mount the differential assembly to the left hand axle arm, using 2 guide pins being careful not to smear gasket sealant. Install and tighten bolts to 41-54 Nm (30-40 ft. lb). Use new bolts with encapsulated adhesive or wire brush the old bolts and apply thread-locking compound, Threadlock and Sealer, EOAZ-19554-M (ESE-M4G20-A) or equivalent. Install support arm tab bolts to side of carrier and tighten to 115-136 Nm (85-100 ft-lbs).
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