DESCRIPTION
Rear axle assembly is semi-floating, hypoid gear type with centerline of pinion set below centerline of ring gear. Axle shafts have integral wheel hubs and are supported in the differential case by side gears and in the axle housing by ball bearings. Service of these assemblies, with exception of axle housing, may be performed without removing complete rear axle assembly from vehicle.
AXLE RATIO IDENTIFICATION
The semi-floating, hypoid gear type rear axle assembly with separate housing is used on all Fiat models, The axle ration is 4.3-1.
REMOVAL AND INSTALLATION
Axle Shafts and Bearings
Removal - 1) Raise vehicle and remove rear wheels and disc brake front shield. Remove caliper support bracket mounting bolt and remove caliper (without disconnecting brake lines). Remove bolts attaching brake disct to axle shaft hub and remove brake disc and plate.
2) Remove snap ring securing bearing dust shield. Attach slide hammer and withdraw axle shaft assembly. Inspect axle shaft bearing, dust shield and bearing retaining collar for wear or damage and replace as necessary.
Disassembly - Using suitable arbor press (A. 74108/1/2), press bearing retaining collar off axle shaft and discard collar. NOTE -Retaining collar must never be reused; replace with new collar. Remove snap ring, dust shield and bearing. If axle shaft is score or damaged, replace shaft.
Reassembly - 1) Install snap ring, dust shield and bearing onto axle shaft held vertically on solid plate of arbor press (A. 74107/1). Insert new collar into suitable holder (A. 74107/4), place in oven and heat to 571°±18°F (300°±10°C). Remove unit from oven and plae on axle shaft. Press axle shaft into collar using 13,000 lb (6,000 kg) maximum pressure.
2) Place axle shaft assembly in tool A. 9560. Position dial indicator to contact hub of axle shaft. Apply 4400 lbs. (2000 kg) axial load with tool A. 95601. Rotate axle by applying 58 to 61.5 ft. lbs. to 8.5 mkg) of torque then check dial indicator reading at opposite end of axle shaft. Reading should remain at zero during rotation of axle shaft.
3) Remove load from axle and recheck dial indicator for zero reading. This will insure that collar has not moved on axle shaft.

Installation - Install new oil seal and "O" ring and complete installation by reversing removal procedure.

FIG 1. CHECKING FIT OF AXLE SHAFT BEARING RETAINER AND AXIAL LOAD

DIFFERENTIAL CARRIER
Removal - Drain fluid, raise vehicle, and remove wheels. Withdraw axle shafts for enough to disengage from side gears. Disconnect propeller shaft, support differential and remove attaching bolts. Remove differential assembly from axle housing.
Installation - Thoroughly clean oil residue from axle housing. Position new gasket in place and reverse removal procedure.
OVERHAUL
Disassembly - 1) With differential secured in suitable holding fixture, remove two bolts and spring washers from caps and remove lock plates. Remove bolts and spring washers securing case bearing caps, and remove caps, adjuster rings and roller bearing cups. Remove differential case from carrier.
2) Turn differential carrier upside down and lock bevel pinion in place. Loosen self-locking nut securing sleeve to bevel pinion shaft and remove sleeve. Remove pinion, thrust ring, rear roller bearing cone and collapsible spacer from inside housing. Remove oil seal, oil slinger, and front bearing cone from carrier.
3) Slide collapsible spacer off pinion, then draw off rear roller bearing .Thrust washer can then be removed from pinion. Using a suitable puller, remove differential case roller bearings. Remove screws holding ring gear to differential case roller bearings. Remove screws holding ring gear to differential case then use drift to remove pinion gear from case. Remove pinion gears, side gears, and thrust washers.
REASSEMBLY AND ADJUSTMENT

FIG 3. CHECKING FOR CORRECT THICKNESS OF WASHER FOR DRIVE PINION DEPTH ADJUSTMENT

Case Assembly - 1) Install thrust washers on differential side gears and position gears in differential case. Insert pinion gears in case and engage them with side gears. Align holes in pinion gears through openings in case and insert pinion shaft. Check axial play in each side gear.
2) Axial play should not exceed .004" (.10 mm). If play exceeds specification, replace side gear thrust washers. These washers are available in various thicknesses. If correct clearance cannot be obtained, gears must be replaced. Assemble ring gear to differential case and torque to specification. Using suitable driver (A. 70152), install both roller bearings on differential case.
Drive Pinion Depth - 1) Fit front and rear roller bearing cups of bevel pinion in position using suitable driver. Using same driver, attach cone of rear roller bearing to dummy pinion (A. 70184) then position dummy pinion in differential carrier.

FIG. 4 LOCATION OF STAMPED NUMBER ON DRIVE PINION GEAR

2) Install cone on front roller bearing and place nut on dummy pinion. Turn pinion to seat bearing cones and tighten nut.
3) Zero dial indicator (A. 95690) on a surface plate then attach to dummy pinion. Position dial indicator to allow plunger to contact roller bearing seat in differential case. Obtain minimum reading on dial indicator by moving plunger from right to left. Record reading and repeat procedure on opposite side.
4) Determine on average from the two readings, then from this average, subtract the value stamped on bevel pinion to be used. This will give correct thickness of thrust washers to be inserted between the head of the pinion and the shoulder of rear roller bearing.
5) If the number stamped on the pinion is preceded by a plus sign, the thickness of the washer to be used is derived by subtracting this number from the dial gauge reading. If the number stamped on the pinion is preceded by a minus sign, the thickness of the washer is obtained by adding this figure to the dial gauge reading.

FIG. 5 CHECKING DIFFERENTIAL BEARING AND RING GEAR BACKLASH

6) Place thrust washer (correct thickness) on bevel pinion, then rear roller bearing cone followed by collapsible spacer. Install pinion assembly in carrier and attach the front roller bearing cone, oil slinger, oil seal, and "U" joint sleeve. Install washer and self-locking nut on tail of pinion.
Pinion Bearing Preload - Secure pinion to keep it from turning. Gradually tighten nut on tail of pinion shat to 87-166 ft. lbs. (12-23 mkg). Check turning torque of pinion shaft using dynamometer (A.95697) and adapter (A. 55075) fitted to pinion nut and set to 17 INCH lbs. (20 cmkg). If turning torque is less than 14 INCH lbs. (16 cmkg), pinion nut must be tightened (without exceeding maximum torque). If turning torque is more than 17 INCH lbs. (20 cmkg), pinion must be removed an collapsible spacer changed.
Backlash and Side Bearing Preload - 1) Place differential side bearing cups on side bearings and place differential assembly into carrier. Fit two bearing retaining and adjusting rings, install caps and torque to specifications.

2) Attach suitable tool (A. 95688) (see illustration), to differential carrier. Adjust backlash between ring gear and pinion to .0031-.0051" (0.08-0.13 mm). Insure that bearings are not preloaded.
3) Set preload by tightening two bearing adjusting rings alternately with equal number of turns until dial indicator "A" (see illustration), shows an increase of .0055-.0071" (0.14-0.18 mm). After preload is set, check backlash of bevel gears.
4) To check backlash, set dial indicator to "B" (see illustration), so that plunger rests against tooth of bevel gear. Rotate gear to obtain maximum reading. Backlash must be .0031-.0051" (0.08-0.13 mm).
Final Inspection and Assembly - With pinion bearing and ring gear backlash properly adjusted, make a tooth contact pattern check. NOTE- Check gear tooth contact using paint impression method described at beginning of this section. When pattern is satisfactory, install axle shafts, brake drums, wheels and tires, propeller shaft and refill with suitable gear lubricant.

Read More..

MODELS COVERED

• XJ6 (1969-74)
• XJ12 (1973-74)
• XKE 4.2 Liter (1968-71)
• XKE V12 (1971-74)

DESCRIPTION
Rear axles are hypoid design with center line of pinion set below centerline of ring gear, Jaguar uses, as standard equipment on XKE models and optional equipment on XJ models, a traction lock or "Powr-Lok" differential which utilizes, clutch discs and plates. All differential adjustments are performed using shims. As independent rear suspension is utilized on all models, stub axles are used for drive output. These stub axles require a shim adjustment also. A collapsible spacer is used on drive pinion shaft.
AXLE RATIO AND IDENTIFICATION
Jaguar uses only one basic rear axle design, however, unit may or may not be fitted with a traction lock device. Also several different axle ratios are used. To determine axle ratio divide number of ring gear teeth by number of pinion gear teeth. Whether or not axle is fitted with traction lock should be determine by owner inquiry or not.
REMOVAL AND INSTALLATION
Rear Suspension Assembly
NOTE - This procedure is provide since may operation on the final drive require removal of rear suspension assembly before starting work or final drive.
1) Raise and support vehicle. Place stands forward of radius arms on body with wood blocks between body and stands. Remove wheels. Remove mufflers from tail pipes. Remove safety wire and bolts securing safety strap to body. Remove radius arm securing bolt, safety strap and radius arm from body mounting post. Disconnect and plug brake lines of body.
2) Remove clevis pin securing hand brake cable to actuating levers on crossmember. Loosen lock nut and remove outer hand brake cable screw from adjuster block. Detach drive shaft from differential. Place jack under rear suspension. Remove bolts and lock nuts securing crossmember mounts to frame. Lower and remove rear suspension from vehicle. To install, reverse removal procedure and note the following: Bleed brakes. Tighten radius arm nuts on lower control arm when weight of vehicle is on wheels.
HALF SHAFT
1) Remove rear suspension assembly. Remove rear hub as follows: Remove fulcrum shaft grease fitting. Withdraw cotter pin and remove nut and washers from splined end of half shaft. Using suitable puller, pull hub and carrier from half shaft. Remove spacer from half shaft and examine inner oil seal track. Replace track if necessary. Remove one nut from outer suspension arm fulcrum shaft and using soft hammer, drift out shaft. Remove hub and carrier assembly from car.
2) Support suspension arm with jack and remove nut and bolt securing top of forward shock absorber. Remove nuts and washer securing shock absorber to suspension arm and remove shock. Remove four nuts securing half shaft flange to stub axle flange and brake rotor. Pull half shaft from suspension unit noting number of camber shims installed between half shaft flange and brake rotor. If necessary, remove joint shields by drilling out rivets.
3) To install, reverse removal procedure, noting the following: If necessary, replace joint shield, positioning grease nipple access hole correctly. Cover joint lines in shield with non-hardening waterproof sealing compound. Be sure to replace camber shims. To reinstall rear hub, proceed as follows: Install suitable dummy shaft (JD.14) in hub carrier fulcrum. Install carrier and suspension arm. Replace outer suspension arm fulcrum shaft, displacing dummy shaft. Secure shaft with nut and reinstall grease nipple.
4) If necessary, install oil seal track to half shaft splined flange, replace spacer. Thoroughly clean and de-grease splines of half shaft and bore of hub. Using a small brush, sparingly apply Lactite "Stud Lock" to outer two thirds of half shaft splines. Assemble hub carrier to half shaft. Install washer and tighten hub carrier assembly nut. Install new cotter pin. Install dial indicator so it bears against hub and zero indicator. Using two levers, pry out on hub and measur hub bearing endfloat. If endfloat exceeds specifications, overhaul rear hub and carrier assembly. After installation of rear suspension in vehicle, check rear wheel camber.
STUB AXLE OIL SEAL
1) Remove half shaft. Remove locking wire and withdraw bolts securing brake caliper to final drive unit. Remove brake rotor, noting number of shims removed between rotor and stub axle flange. Remove lock wire and five bolts securing caliper mounting bracket. Withdraw drive shaft, together with caliper mounting shims, ball bearing and oil seal. Turn down tab washer and remove nut from stub axle. Remove ball bearing and caliper mounting bracket stub axle.
2) Lightly oil new seal and position carefully in final drive case. Press seal squarely and fully seat in case groove. Do NOT remove protruding portion of seal. Coat seal with hypoid oil and place caliper mounting bracket and seal assembly over stub axle. Slide ball bearing on drive shaft followed by new tab washer and nut. Ensure bearing seats square to stub axle shoulder and tighten nut. Turn up tab on washer.
3) Lightly oil stub axle splines and install shaft in final drive housing. Install bolts securing mounting bracket finger tight. Using feeler gauges, measure dimension between inside face of mounting bracket and final drive housing. The measurement obtained determines shim thickness required. Remove stub axle and select shims of required thickness, and thinly coat mating faces and shims with suitable sealant (Hylomar). Tighten bolts in a diagonal sequence.
4) Wire lock securing bolts to tension in clockwise direction. Install brake rotors and half shaft flange, using shims removed from between rotor and flange. Install caliper on mounting bracket. Install suitable distance spacers (oversize nuts) to rotor studs and tighten nuts. Use feeler gauge to ensure that rotor is centrally located between jaws of caliper. If necessary add to or remove from shim pack between flange and disc to center rotor. Continue assembly in reverse of disassembly procedure.
PINION FLANGE AND SEAL
1) Disconnect propeller shaft. Check and record torque required to turn drive shaft falnge clockwise (viewed from front) through backlash movement. Chock rear wheels and remove flange securing nut and washer. Remove flange. Pry oil seal out of final drive case. Lightly score oil seal recess with tang of file.
2) Ensure oil seal recess is clean and free of oil. Lightly top new oil seal into recess ensuring seal is square with case. Reinstall falnge, washer and nut. Tighten nut to 120 ft. lbs. (16.5 mkg) while rotating flange to ensure bearing seats correctly. Again check pinion preload. If preload is below specifications, continue tightening flange nut until specified preload is obtained. However, if preload exceeds maximum specified value, new collapsible spacer must be installed, see differential overhaul. Reconnect shaft and remove wheel chocks.
FINAL DRIVE UNIT
1) Remove rear suspension assembly and drain final drive unit. Remove final drive mounting plate and shock absorber/spring units. Remove nuts securing half shaft inner universal joint to brake rotor and disconnect half shaft, noting shims removed. Remove nut from inner suspension arm fulcrum shaft and drift out shaft. Repeat for other side of unit. Disconnect and plug brake lines. Disconnect hand brake levers from compensator.
2) Remove locking wire from final drive mouting bolts, remove bolts and crossmember by tilting forward over pinion. Remove calipers from final drive unit. Remove brake rotors, noting number of shims removed from between rotor and stub axle flange. To install, reverse removal procedure making sure brake rotor is centered between jaws of caliper and wire lock tension bolts in clockwise direction.
OVERHAUL
Disassembly
1) Remove rear cover and discard gasket. Remove lock wire and bolts securing caliper mounting braket. Withdraw stub axle along with caliper mounting bracket shims, ball bearing and oil seal. Turn down tab washer and remove nut, ball bearing and caliper mounting bracket from stub axle. Repeat procedure for second stub axle. Remove bolts securing differential bearing caps and lift off caps. Pry out differential assembly using two levers and taking care not to damage housing.
2) Remove drive pinion nut and washer. Mark relative positions of flange and pinion and remove flange. Using a suitable press, remove pinion from differential housing. Remove oil seal, oil thrower and outer bearing cone. Examine inner and outer bearing cups for wear. If replacement is required, extract cups, using suitable tools (SL 14 and SL 14/1). NOTE - If removal of bearing cups is difficult, gently heat final drive housing in rear of bearing cups. On "Powr-Lok" differentials only, proceed as follows.
3) Remove differential side beaings using suitable tools (SL. 14 & 14/3). If no reference marks are present, scribe a line across both halves of differential case to ensure correct reassembly. Remove bolts securing bolts halves of differential case. Split case and remove clutch discs and plates from one side. Remove differential side ring, pinion side gear and pinion cross shafts complete with gears. Remove remainin side gear and ring and extract remaining clutch discs and plates.
4) On non "Powr-Lok" differentials only, remove peening and drift pinion shaft lock pin out of carrier. Remove gears, shaft and shims from carrier.
REASSEMBLY AND ADJUSTMENT

"POWR-LOK" CASE ASSEMBLY

Case Assembly - 1) On "Powr-Lok" differentials, install clutch plates and discs alternately into flange half of case. Install two belleville clutch plates so that convex sides are against case. Install side ring and position one side gear into ring recess. Install cross shafts. Install pinion cross shafts complete with pinion gears ensuring that ramps on shafts coincide with mating ramps in case.
2) Assemble differential case halves ensuring that reference marks are lined up and clutch friction plate tongues are aligned with grooves in differential case. Install bolts but do not tighten yet. Check alignment of splines by inserting both stub axles. Tighten differential case bolts with stub axles in position. With one stub axle locked, other axle must not turn more than .75" (.19 mm) measured on a 6" (152 mm) radius.
3) On non "Powr-Lok" differentials, install pinion shaft, shims and gears into differential carrier. Secure lock pin by peening.

MEASURING SIDE BEARING PRELOAD

Side Bearing Preload - Install differential side bearings, without shims, on differential case, making sure that bearings and housing are perfectly clean. Place differential assembly in housing. Install dial indicator with indicator leg against back face of ring gear. Using suitable pry bars between housing and bearing cups, move differential assembly fully to one side of housing. Zero dial indicator and move assembly ot other side. Record indicator reading and add .009" (.20 mm) to reading to give total shim pack required. Remove differential assembly from housing.
Drive Pinion Depth - 1) Place pinion, together with inner bearing cone, into housing. Turn housing over and support pinion. Install pinion outer bearing cone, flange, washer and nut, omitting collapsible spacer, oil slinger and oil seal, tighten nut. Using suitable dial indicator support fixture (SL3) zero dial indicator on setting block (4.H.A.). Place dial indicator fixture firmly on face of pinion and note dial indicator reading to bottom of housing bearing bore (see illustration).
2) The indicator reading shows deviation of pinion setting from zero cone setting. This value should agree with value etched on face of pinion at bottom. For example, if value etched on pinion is -2, dial indicator should read - .002". If setting is incorrect, dismantle pinion and remove pinion inner bearing cup. Add or remove shims as required, reassemble and recheck pinion depth.
3) When setting is correct, extract pinion from housing sufficiently far to remove outer bearing cone. Install collapsible spacer to pinion ensuring that it seats firmly on machined shoulder of pinion. Insert pinion into housing, install outer bearing cone, oil slinger and oil seal. Lightly grease splines of pinion shaft and install flange. Install new washer on end of pinion with convex side facing end of shaft. Install but DO NOT tighten nut.

MEASURING PINION DEPTH

Backlash Adjustment - 1) Place differential assembly, complete with side bearings but less shims, in housing. Ensure that bearings and housing are perfectly clean. Install dial indicator on housing with feeler on back face of ring gear. Pry differential case and ring gear assembly away from pinion until opposite side bearing is seated against housing. Zero dial indicator at this point.
2) Move differential assembly towards pinion until ring gear is deeply meshed with pinion. Note indicator reading and from this value, subtract the backlash allowance etched on drive gear (eg. B/L.007 denotes .007"). This result will yield the thickness of shims (in inches) to be placed between differential case and side bearing on ring gear side of differential. Install this thickness of shims, taking shims from pack determined previously under "Side Bearing Preload". Install balance of total shims required on opposite side of case. An example of calculations required as follows
EXAMPLE
Side Bearing Preload Reading........................... .080"
PLUS Preload Value........................................ .009"
Total Shim Pack............................................. .089"
Pinion-to-Ring Gear Clearance.......................... .042"
MINUS Etched Backlash Value......................... .007"
Total Ring Gear Side Shims.............................. .035"
Total Shim Pack.............................................. .089"
MINUS Ring Gear Side Shims.......................... .035"
Opposite Ring Gear Shim Pack......................... .050"

MEASURING RING GEAR SIDE SHIM THICKNESS

3) With shims calculated installed, lower differential assembly into position, lightly tapping bearing home with soft hammer. Make sure ring and pinion gears mesh as installation proceeds. Install side bearing cap bolts. Mount dial indicator on housing with feeler against back face of ring gear. Turn pinion by hand and check ring gear run out. If run out exceeds specifications, disassemble differential, clean all mounting surface and check for burrs.
4) Now place dial indicator to measure ring gear backlash. Move ring gear and check that backlash is to specification etched on ring gear. If backlash is not to specifications, transfer necessary shims from side of differential case to the other NOTE - To increase backlash, remove shims from ring gear side and install on opposite side and visa versa. Finally, run a gear tooth contact pattern and adjust shims as necessary.

Pinion Bearing Preload - Install pinion and stub axle oil seals. Install stub axles following procedure give under stub axle removal and installation. Tighten flange to ensure correct seating of taper roller bearings. Use care not to overtighten nut. If not is overtighten, install a new collapsible spacer as pinion bearing preload will otherwise be incorrect. Install final drive rear cover using new gasket and suitable sealer (Hylomar).

MEASURING RING GEAR BACKLASH

Read More..