Assemble

Reassembly

NOTE: Before commencing assembly, check from reference numbers and letters that pinion and drive gear are a matched pair.

Fig.38:

The same serial number must be marked on the pinion end and the outer periphery of the crown wheel (1, Fig.38), (e.g. 7029). If these requirements are not met the unit must be exchanged.

Powr-Lok only

Prior to reassembly coat all plates and discs with Powr-lok oil.

Fig.39:

Refit two Belleville clutch plates (2, Fig.39) so that convex sides are against differential casing.

Refit clutch plates (4, Fig.39) and discs (3, Fig.39) as shown into each half of the casing.

Fit side ring (5, Fig.39). Position one side gear into ring recess (6, Fig.39). Fit cross-shafts.

Refit pinion mating cross-shafts complete with pinion gears ensuring that ramps on the shafts coincide with the mating ramps in the differential case (7, Fig.39).

Assemble remaining side gear (6, Fig.39) and ring (7, Fig.39).

Offer up right-hand half of differential case (8, Fig.39) to flange half in accordance with identification marks and position clutch friction plate tongues so that they align with grooves in differential case.

Assemble righthand half to flange half of differential case using eight bolts coated with Loctite 275 but do not tighten at this stage (9, Fig.39).

Fig.40:

Tighten eight bolts to a torque of 6.05 to 6.9 kgf/m (43 to 50 lb/ft) while drive shafts are in position (1, Fig.40).

Fig.41:

With one drive shaft locked, the torque to turn the other (2, Fig.41) should be between 40 lb/ft and 70 lb/ft. e.g. hold one shaft in vice soft jaws whilst turning the other.

NOTE: Ensure that prior to assembly the crown wheel mounting face is free from damage or burrs, particularly on the edge; should any burns be left on the carrier they must be removed with an oil stone prior to fitment of the crown wheel.

Fit the crown wheel to the carrier diametrically using the ten bolts and tab washers, torque up the bolts to 10.78 to 12.4 kgf/m (77 to 88 lb/ft).

Thickness of shims required in the installation of the differential side bearings is determined as follows:

Fig.42:

Fit the differential side bearings (1, Fig.42) using tools 18G 134 (2, Fig.42) and SL 550-1 (3, Fig.42) without the shims onto the differential case, making sure that the bearings and housing are perfectly clean.

Place the differential assembly with the bearings in their housing into the differential case without the pinion in position.

Fig.43:

Install a dial indicator gauge setting the button against the back face of the crown wheel (1, Fig.43).

Inserting two levers between housing and the bearing cups, move the differential assembly to one side of the carrier. Set the dial indicator to zero.

Move the assembly to the other side and record indicator reading, giving total clearance between bearings, as now assembled, and abutment faces of the gear carrier housing.

Remove differential assembly from the gear carrier.

Fig.44:

Fig.45:

Re-install the pinion outer hearing cup using tools 18G 134 (1, Fig.44 & 45) and SL 550-9 (2, Fig.44 & 45).

Fig.46:

Fit the inner bearing cup (1, Fig.46) and shims using tools 18G 134 and SL 55O-8 (2, Fig.46).

Fig.47:

Press the inner bearing cone onto the pinion using tools 47 (1. Fig.47), SL 47-1/1 (2, Fig.47) and SL 47-1/2 (3, Fig.47).

NOTE: The hypoid drive pinion must be correctly adjusted before attempting further assembly, the greatest care being taken to ensure accuracy.

Fig.3d:

The correct pinion setting is marked on the ground end of the pinion. The matched assembly serial number is also marked on the periphery of the crown wheel, and care should be taken to keep similarly marked gears and pinions in their matched sets as each pair is lapped together before despatch from the factory. The letter on the left is a production code letter and has no significance relative to assembly or servicing of any axle. The letter and figure on the right refer to the tolerance on offset or pinion drop dimension, which is stamped on the cover facing of the gear carrier housing. The number at the bottom gives the cone setting distance of the pinion and may be Zero (0). Plus (+) or Minus (-) (Fig.48).

When correctly adjusted a pinion marked Zero will be at the zero cone setting distance dimension which is 66.67 mm (2.625 in) (i.e. from the centre line of the gear to the face on the small end of the pinion. A pinion marked Plus two (+2) should be adjusted to the nominal (or Zero) cone setting plus 0.0508 mm (0.002 in) and a pinion marked Minus two (-2) to the cone setting distance minus 0.0508 mm (0.002 in). Thus for a pinion marked Minus two (-2) the distance from the centre of the drive gear to the face of the pinion should be 66.619 mm i.e. 66, 67 - 0.0508 mm (2.623 in i.e. 2.625 - 0.002 in) and for a pinion marked Plus three (+3) the cone setting distance should be 66.746 mm (2.628 in). Place pinion, together with inner bearing cone, into gear carrier.

Fig.49:

A Pinion drop 38.1 mm (1.5 in).
B Zero cone setting 66.67 mm (2.625 in).
C Mounting distance 108.52 mm (4.312 in).
D Centre line to bearing housing 139.57 mm (5.495 in) to 139.83 mm (5.505 in).

Turn carrier over and support pinion with a suitable block of wood for convenience before attempting further assembly.

Fit pinion outer bearing cone, companion flange, washer and nut only, omitting the collapsible spacer, oil thrower and oil seal, and tighten nut to remove all backlash.

Fig.50:

Check pinion setting distance by means of gauge tool SL3 (1, Fig.50). Adjust bracket carrying dial indicator using 4HA setting block. For differentials with a white painted circle on the rear cover use tool no. SL2. (2, Fig.50) and set dial face to zero.

Check pinion setting by taking a dial indicator reading on the differential bearing bore with the assembly firmly seated on the ground face of the pinion (3, Fig.50). The correct reading will be the minimum obtained; that is, when the indicator spindle is at the bottom of the bore. Slight movement of the assembly will enable the correct reading to be easily ascertained. The dial indicator shows the deviation of the pinion setting from the zero cone setting and it is important to note the direction of any such deviation as well as the magnitude.

If pinion setting is incorrect it is necessary to dismantle the pinion assembly and remove the pinion inner bearing cup. Add or remove shims as required from the pack locating the bearing cup and re-install the shim pack and bearing cup. Adjusting shims are available in thicknesses of 0.076 mm, 0.127 mm and 0.254 mm (0.003 in., 0.005 in. and 0.010 in.). Repeat setting operations until satisfactory result is obtained.

Extract pinion shaft from gear carrier far enough to enable the outer bearing cone to be removed from the pinion.

Fit the collapsible spacer to the pinion ensuring that it seats firmly on the machined shoulder on the pinion shaft.

Fig.51:

Insert pinion into gear carrier. Refit the outer bearing cone, oil thrower and using tool 18G 1428 (1, Fig.51) fit the oil seal. Loctite the splines of the pinion shaft and fit the flange. Fit a new washer, convex face outermost. Fit, but DO NOT tighten the flange retaining nut.

Begin tightening the flange nut, stopping at frequent intervals to check the torque required to turn the pinion, using the string and spring balance, until the required torque is obtained.

The flange nut may have to be tightened to as much as 18 kgf/m (130 lbf/ft).

Torque required to turn pinion bearings and oil seal:

Old bearings - 0.20 to 0.28 kgf/m (20 to 25 lbf/in).
New bearings - 0.35 to 0.46 kgf/m (30 to 40 lbf/in).

Note the actual figure required to turn the pinion.

If the above values are exceeded a new collapsible spacer must be fitted. ON NO account must the nut be slackened off and retightened as the collapsed spacer will not then sufficiently clamp the bearing cones. Place differential assembly complete with side bearings but less shims, in the housing. Ensure that bearings and housing are perfectly clean.

Fig.52:

Using the shim pack previously selected, vary the shim thicknesses between each bearing cup and the carrier face to achieve a backlash of 0.15 to 0.25 mm (0.006 to 0.010 in.) measured at the outer edge of the ring gear (Fig.52).

Add an additional 0.07 mm (0.003 in.) shim to each pack and carefully note form which side of the differential case the pack was removed.

Remove the bearing cups and cones from the differential case using SL 14-3/2 and SL 14-3/1.

Fit appropriate shim pack to the differential case and refit the bearing cone.

Ensure that the matching shim pack and cone are fitted to the same side of the differential housing that they were removed from.

Lower differential assembly into position lightly tapping the bearings home with a hide hammer.

NOTE: Ensure that gear teeth are led into mesh with those of the pinion. Careless handling at this stage may result in bruising the gear teeth. Removal of the consequent damage can only be partially successful and will result in inferior performance.

Fig.53:

When refitting side bearing caps, ensure that position of the numerals marked on gear carrier housing face and side bearing cap coincide (1, Fig.53).

Tighten cap bolts to a torque of 8.82 to 10.08 kg/m (63 to 72 lb/ft) (2, Fig.53).

Fig.54:

Mount a dial indicator on gear carrier housing with the button against back face of gear (1, Fig.54).

Turn pinion by hand and check run out on back face of gear. Run out should not exceed 0.13 mm (0.005 in.). If run out excessive, strip the assembly and rectify by cleaning the surfaces locating the drive gear. Any burrs on these surfaces must be removed.

Fig.55:

Remount dial indicator on gear carrier housing with button tangentially against one of drive gear teeth (1, Fig.55).

Move drive gear by hand to check backlash which should be 0.15 to 0.25 mm (0.006 to 0010 in.). If backlash is not to specification, transfer the necessary shims from one side of the differential case to the other to obtain the desired setting. Check backlash in at east four positions of drive gear, ensuring that backlash is always greater than 0.15 mm (0.006 in.).

Check that the torque to turn the input flange is 1.4 to 2.8 kgf/m (10 to 20 lbf/in) additional to the torque measured previously to turn the pinion.

Smear cover flange only with Welseal jointing compound, place gasket on final drive casing, place cover over gasket and insert two bolts to retain, coating threads with Loctite.

Replace remaining eight bolts, coating threads with Loctite and replace the tabs. Tighten screws by diagonal selection to correct torque 2.1 to 2.8 kgf/m (15 to 20lbf/ft).

Fig.56:

Fig.57:

Refit both output shaft assemblies (1, Fig.56) and torque the bolts to 8.4 to 9.66 kgf/m (60 to 69 lbf/ft), replace the drain plug and refit the drive unit to the crossmember (1, Fig.57).

Fig.58:

Secure with bolts (1, Fig.58) torque and lockwire (2, Fig.58). ensuring that when lockwired, the wire is tightening the bolts. After refitting the unit to the vehicle fill with new oil.