Overhaul
NOTE: The front and rear differentials fitted to Range Rover are the same type. This procedure applies to both.DISASSEMBLE
It is essential that differential components are marked in their original positions and relative to other components so that, if refitted, their initial setting is maintained. Note that the bearing caps must not be interchanged.
1. Remove the axle shafts then the differential assembly from the axle.
2. Drive out the roll pin securing the bearing nut locking fingers to the bearing caps. Remove the locking fingers.
3. Loosen the bearing cap bolts and mark the caps for re-assembly.
4. Using service tool R0530105, remove the bearing adjusting nuts.
5. Remove the bearing cap bolts and bearing caps.
6. Lift out the crown wheel (ring gear), differential unit and bearings.
7. Remove the cotter pin securing the pinion flange nut.
8. Remove the pinion flange nut using service tool 18G1205 to restrain the flange.
9. Withdraw the pinion complete with pinion head bearing and outer bearing shims. Withdraw the shims.
10. Remove the pinion flange oil seal, spacer and bearing. Discard the oil seal.
11. Using service tool R0262757A, remove the pinion head bearing track and shim and drive out the outer bearing track from the differential housing.
12. Remove the pinion head bearing with service tool MS47 and adaptor 18C47-6.
13. Remove the bolts and washers securing the crown wheel to the differential flange. Withdraw the crown wheel.
14. Remove the differential carrier bearings.
15. Remove the circlips securing the differential cross shaft. Extract the cross shaft.
16. Withdraw the differential gears and pinions.
17. Thoroughly clean all components.
Inspection
18. Check all bearings for wear and/or pitting.
19. Check all gears for wear, scuffing, pitting and damaged teeth.
20. Note that the crown wheel and pinion are supplied as a matched set, also the pinion housing and bearing caps.
REASSEMBLE
Differential Gears
21. Fit the differential gears to the differential housing.
22. Fit the differential cross shaft and retaining circlips.
23. Check the gear for freedom of rotation and backlash. Nominal backlash should be present. Excessive backlash will necessitate replacement of the gears and/or the differential housing. No provision is made for backlash adjustment.
24. Check that the serial number marked on the pinion end face matches that marked on the crown wheel.
25. Ensuring that the differential housing flange and crown wheel are thoroughly clean fit the crown wheel.
26. Fit the carrier bearings using a suitable press or drift and assemble the tracks (races) to the bearings.
27. Place the differential housing complete with crown wheel and bearings in the pinion housing.
28. Fit the bearing caps and bolts. Do not fully tighten the bolts.
29. Fit the bearing adjusting nuts and adjust to obtain zero end-float.
30. Tighten the bearing cap bolts to 80-100 Nm (59-74 ft lbs).
31. Using a dial gauge check the crown wheel for run-out. This should not exceed 0.10 mm (0.004 in). If excessive run-out is recorded remove the crown wheel and examine crown wheel and mounting flange for burrs, grit, etc. Refit the crown wheel and recheck. Run-out, attributable to a buckled or damaged differential housing flange can be corrected only by replacing the differential gear housing.
32. When satisfied that run-out is within the specified limits remove the differential housing from the pinion housing.
33. Remove the crown wheel bolts and refit them using Loctite(r) Studlock. Evenly tighten the bolts to 55-61 Nm (40-45 ft lbs).
34. Fit the pinion head bearing track and the original shim to the pinion housing using service tools R0262757A and R0262757-1. If the original shim was damaged or mislaid use a new shim of at least 1.27 mm (0.050 in) thickness.
35. Fit the pinion outer bearing track to the pinion housing with service tools R0262737A and R0262757-2.
36. Fit the pinion head bearing to the pinion using service tool 18G47-6.
37. Enter the pinion into its location in the pinion housing. Do not fit the shims for bearing pre-load at this stage.
38. Fit the outer bearing and spacer.
39. Fit the driving flange, washer and nut.
40. Do not fit the oil seal at this stage.
41. Tighten the pinion flange nut slowly until the force required to rotate the pinion is 23 to 40.25 kgf cm (20 to 35 in lb) if new bearings are fitted. This will pre-load the bearings in order to check the pinion height dimension.
NOTE: If using original bearings, which are bedded in, the pre-load figure is 11.5 to 17.25 kgf cm (10 to 15 in lb)
Drive Pinion Markings
42. The markings on the end face adjacent to the serial number are of no significance during servicing.
43. The figure marked on the end face opposite to the serial number indicates, in thousandths of an inch, the deviation from nominal required to correctly set the pinion. A pinion marked plus (+) must be set below nominal, a minus (-) pinion must be set above nominal. An unmarked pinion must be set at nominal.
44. The nominal setting dimension is represented by the setting gauge block 18G191-4 which is referenced from the pinion end face to the bottom radius of the differential bearing bore.
Drive Pinion Adjustment
45. Ensure that the pinion end face is free of raised burrs around the etched markings.
46. Remove the keep disc from the magnetized base of dial gauge tool 18G191.
47. Place the dial gauge and setting block on a flat surface and zero the dial gauge trace pin on the setting block. Use of a surface plate is recommended.
NOTE: The setting block has three setting heights as follows. Use only the 39.50mm setting mark for this differential.
PINION HEIGHT SHIMS
PART No. INCH MM
549230 .038 0.97
549232 .040 1.02
549234 .042 1.07
549236 .044 1.12
549238 .046 1.17
549240 .048 1.22
549242 .050 1.27
549244 .052 1.32
549246 .054 1.37
549248 .056 1.42
549250 .058 1.47
549252 .060 1.52
576236 .062 1.57
576237 .063 1.60
576238 .064 1.63
576239 .065 1.65
48. Position the dial gauge centrally on the pinion end face with the trace pin registering on the lowest point on one differential bearing bore. Note the dial gauge deviation from the zeroed setting.
49. Repeat on the other bearing bore. Add together the readings then halve the sum to obtain the mean reading. Note whether the trace pin has moved up or down from the zeroed setting.
a. Where the trace pin has moved down, the amount is equivalent to the thickness of shims that must be removed from under the pinion inner track to bring the pinion down to the nominal position.
b. Where the trace pin has moved up, the amount is equivalent to the additional thickness of shims required to bring the pinion up to the nominal position.
INCH MM
.001 = .025
.002 = .05
.003 = .075
.004 = .10
.005 = .125
.006 = .15
.007 = .175
.008 = .20
.009 = .225
.010 = .25
NOTE: DIAL INDICATOR IS METRIC! Conversion must be made to SAE (INCH) UNITS when performing measurements and selecting shims.
50. Before adjusting the shim thickness, check the pinion face marking and if it has a plus (+) figure, subtract that amount in thousandths of an inch from the shim thickness figure obtained in the previous item.
51. Alternatively, if the pinion has a minus (-) figure, add the amount to the shim thickness figure. Adjust the shim thickness under the pinion head bearing track as necessary.
52. Recheck the pinion height setting. If the setting is correct, the mean reading on the dial gauge will agree with the figure marked on the pinion end face. For example, with an end face marking of + 3, the dial gauge reading should indicate that the pinion is +0.003 in.
Bearing Pre-Load Adjustment
53. Remove the pinion flange, pinion, outer bearing and spacer.
54. Slide new shims, of the same thickness as the originals (bearing pre-load) into position on the pinion shaft. If the original shim was damaged or mislaid use a new shim of at least 4.06 mm (0.160 in) thickness.
55. Enter the pinion in its location in the pinion housing and fit the outer bearing and spacer.
56. Fit the driving flange, washer and nut.
57. Do not fit the oil seal at this stage.
58. Tighten the pinion flange nut to 36-46 Nm (26-34 ft lbs). The force required to rotate the pinion shaft should be within 23 to 40.25 kgf cm (20 to 35 in lb) using new bearings, when initial inertia has been overcome. Change the bearing pre-load shim as necessary to obtain this requirement. A thicker shim will reduce pre-load; a thinner shim will increase pre-load.
NOTE: If using original bearings, which are bedded in, the pre-load figure is 11.5 to 17.25 kgf cm (10 to 15 in lb).
59. Remove the pinion flange.
PINION PRELOAD SHIMS
PART No. INCH MM
FRC1193 .060 1.52
FRC1195 .062 1.57
FRC1197 .064 1.63
FRC1199 .066 1.68
FRC1201 .068 1.73
FRC1203 .070 1.78
539718 .072 1.83
539720 .074 1.88
539722 .076 1.93
539724 .080 2.03
Fitting Pinion Oil Seal
CAUTION: Before fitting the new seal to the differential, examine the seal to ensure that it is clean, undamaged and that the garter spring is properly located. A small scratch on the seal lips could impair its efficiency.
60. Coat the outer diameter of the new seal width with an all purpose grease and fit the seal, lip side leading squarely on the pinion nose housing and drive the seal into position flush with the end face of the housing using seal replacing tool LST106.
61. Lightly lubricate the seal lips with a recommended oil. Fit the distance piece and flange and secure with washer and nut. Tighten the nut and fit a new cotter pin.
Crown Wheel/Pinion Backlash
62. Place the differential housing in the pinion housing.
63. Fit the bearing caps and bolts. Do not fully tighten the bolts.
64. Fit the bearing adjusting nuts.
65. Push the crown wheel into mesh with the pinion, loosening the left hand bearing adjuster nut, using service tool 530105.
66. Tighten the right hand nut until crown wheel/pinion backlash is just removed.
67. Tighten the left hand nut slowly until it contacts the bearing. Continue turning the left hand nut until a backlash of 0.10 to 0.17 mm (0.004 to 0.007 in) is achieved. DO NOT slacken the right hand nut at any time, otherwise the bearing preload will be affected.
Caution should also be taken when performing backlash setup i.e. convert metric readings to inches.
68. Fit the locking fingers and roll pins. If necessary, tighten the adjustment nuts slightly to align the locking finger with a slot.
69. Evenly tighten the bearing cap bolts to 80-100 Nm (59-74 ft lbs).
70. Recheck crown wheel/pinion backlash,
71. Lubricate the bearings and gears.
Pinion Bearing Pre-load Data
New bearings 23 to 40.25 kgf cm (20 to 35 in lb)
Bearings bedded in 11.5 to 17.25 kgf cm (10 to 15 in lb)
Crown wheel run-out 0.10 mm (0.004 in)
Crown wheel/pinion backlash 0.10 to 0.17 mm (0.004 to 0.007 in)