Front Differential
UNIT REPAIR
DISASSEMBLY
1. Remove front drive shaft by using plastic hammer.
2. Remove 8 bolts for fastening differential carrier (2 of which are reamer bolts) and then take differential assembly out of housing.
3. Set special tool on vise securely.
Special Tool
(A): 09944-76010
4. Using 4 bolt & nut sets, set differential assembly onto differential carrier holder and put identification marks on differential side bearing caps. Remove differential inner hose and actuator bracket bolt.
5. Take off differential side bearing lock plates and differential side bearing caps removing their bolts and then take out bearing adjusters, side bearing outer races and drive bevel gear with differential case.
6. Turn differential assembly together with special tool by 90 degrees and grip it with vise again.
Special Tool
(A): 09944-76010
7. Remove air inlet union.
8. Hold universal joint flange with special tool and then remove flange nut by using power wrench.
Special Tool
(B): 09922-66020
9. Make mating marks on drive bevel pinion and companion flange.
CAUTION: Don't make mating mark on the coupling surface of the flange.
10. Remove companion flange from pinion. Use special tool if it is hard to remove.
Special Tool
(C): 09913-65135
11. Remove bevel pinion with front bearing, and spacer from carrier.
If it is hard to remove, screw an used nut into pinion and hammer on that nut with a plastic hammer but never directly on pinion.
12. Using special tools, pull out differential side bearings.
Special Tool
(D): 09913-85230
13. With aluminum plates placed on vise first, grip differential case with it and remove bevel gear by removing its 10 bolts.
CAUTION: Use care not to hold axle lock clutch part with vise. Be sure to hold differential left case.
14. Separate differential case assembly by removing 2 screws and take out free axle hub, side gears and shims from differential left case.
15. Remove bevel pinion front bearing by using bearing puller and press.
16. Drive out bevel pinion bearing outer races in differential carrier by hammering metal stick applied to them.
INSPECTION
- Check companion flange for wear or damage.
- Check bearings for wear or discoloration.
- Check differential carrier for cracks.
- Check drive bevel pinion and bevel gear for wear or cracks.
- Check side gears, pinion gears and pinion shaft for wear or damage.
- Check side gear spline for wear or damage.
DIFFERENTIAL LEFT CASE
Check clutch for smooth movement by pushing plate of axle lock clutch fitted to differential left case. Also, check return spring for settling.
Check teeth of axle lock clutch fitted to differential right case for wear, damage and any other faulty condition.
FREE AXLE HUB
Check teeth of free axle hub for wear, damage and any other faulty condition.
ACTUATOR
1. Connect special tool, air compressor, actuator and hoses as shown in figure.
NOTE: Loosen adjusting screw of special tool before connecting hoses to special tool.
Special Tool
(A): 09918-18110
2. With pressure from compressor applied to special too, adjust pressure to specified level by turning adjusting screw of special tool and check actuator for operation. Also, check that there is no air leakage from actuator.
Specified pressure: 38.0 kPa (0.38 kg/cm2, 5.40 psi)
Actuator stroke : 3 mm (0.118 inch)
ADJUSTMENT AND REASSEMBLY
Judging from faulty conditions noted before disassembly and what is found through visual check of bearing and gear tooth etc. after disassembly, prepare replacing parts and proceed to reassembly according to procedures as described below.
CAUTION:
^ Bevel gear and pinion must be replaced as a set when either replacement becomes necessary.
^ When replacing taper roller bearing, replace as inner race & outer race assembly.
DIFFERENTIAL CARRIER
For press-fitting bevel pinion bearing outer races, use special tools as shown.
CAUTION: Perform press-fitting carefully so as not to tilt outer race.
Special Tool
(A): 09924-74510
(B): 09926-68310
(C): 09913-75510
DIFFERENTIAL CASE ASSEMBLY
1. Install differential gears, free axle hub and washers to left case.
2. Install left case to right case and tighten screws.
3. Put bevel gear on differential case and fasten them with 10 bolts by tightening them to specified torque. Use thread lock cement for 10 bolts.
CAUTION: Use of any other bolts than that specified is prohibited.
"A": Thread lock cement 99000-32020
Tightening Torque
(a): 85 Nm (8.5 kg-m, 61.5 ft. lbs.)
4. Press-fit side bearing with special tool and press.
Special Tool
(G): 09944-66020
5. Install actuator to differential case.
NOTE: Note that installing direction is as shown in figure.
6. Hold bearing press-fitted in step 7 with holder and press-fit side bearing on the other side.
NOTE: Be sure to use bearing holder for the purpose of protecting lower bearing.
Special Tool
(G): 09944-66020
(H): 09951-16060
DRIVE BEVEL PINION
To engage bevel pinion and gear correctly, it is prerequired to install bevel pinion to differential carrier properly by using adjusting shim as described on following pages. Shown above are relative positions of bevel pinion, differential carrier and mounting dummy.
1. Install bevel pinion dummy with bearings into differential carrier and tighten flange nut so that specified bearing preload is obtained.
NOTE:
^ This installation requires universal joint flange not equipped with groove on flange periphery.
^ This installation requires no spacer or oil seal.
^ Before taking measurement with spring balance or torque wrench, check for rotation by hand and apply small amount of oil to bearings.
Special Tool
(A): 09922-75222
(B): 09926-78311
Pinion bearing preload
(a): 9.0 - 17.0 kg-cm (7.8 - 14.7 inch lbs.)
Spring measure reading: 1.8 - 3.4 kg (4.0 - 7.5 lbs.)
2. Set dial gauge to bevel pinion mounting dummy and make 0 (zero) adjustment on surface plate.
NOTE:
^ When setting dial gauge to mounting dummy, tighten screw lightly. Be careful not to overtighten it, which will cause damage to dial gauge.
^ With dial gauge set, turn dummy back and force by hand a couple of times and attain accurate 0 (zero) adjustment.
^ It is desirable that short pointer indicates beyond 2 mm when long one is at 0 (zero).
Special Tool
(C): 09926-78311
(D): 09900-20606
3. Place zero-adjusted mounting dummy and dial gauge set on pinion dummy and take measurement between zero position and extended dial gauge measuring tip.
NOTE:
^ Repeat turning back and force of dummy and measure distance as far as top surface of pinion dummy accurately.
^ When dial gauge measuring tip extends from 0 (zero) position, pointer turns counterclockwise.
^ Measured value may exceed 1 mm. Therefore, it is also necessary to know reading of short pointer.
Special Tool
(C): 09926-78311 (Mounting dummy)
(B): 09900-20606 (Dial gauge)
4. Obtain adjusting shim thickness by using measured value by dial gauge (which represents "c") in the following equation.
94 in above equation is "a" + "b" of mounting dummy (special tool) as shown.
5. Select adjusting shim(s) closest to calculated value from among following available sizes and put it in place and then press-fit front bearing.
Special Tool
(E): 09925-18010
(F): 09927-66010
6. With new pinion spacer inserted as shown, install rear bearing to differential carrier.
NOTE:
^ Make sure to use new spacer for reinstallation.
^ Apply oil to bearings.
7. Using special tool and plastic hammer drive oil seal into differential carrier till it becomes flush with carrier end.
Then apply grease to oil seal lip.
Special Tool
(G) 09951-18210
"A" Grease 99000-25010
8. While tightening flange nut gradually with flange holder (special tool) and power wrench, set preload of pinion to specification.
NOTE:
^ Before taking measurement with spring balance or torque wrench, check for smooth rotation by hand.
^ Bearing preload can be measured roughly by pinion rotating angle which is due to arm weight of flange holder installed in flange.
Refer to following page for further information.
^ Be sure to tighten gradually and carefully till specified starting torque is obtained. Turning back overtightened flange nuts should be avoided.
Pinion bearing preload: 9.0 - 17.0 kg-cm (7.8 - 14.7 inch lbs.)
Spring measure reading: 1.8 - 3.4 kg (4.0 - 7.5 lbs.)
Special Tool
(A): 09922-75222
(H): 09922-66020
ASSEMBLING UNIT
1. Apply sealant to thread part of air inlet union and install it to differential carrier. Tighten it to specified torque
"A": Sealant 99000-31110
Tightening Torque
(a): 13 Nm (1.3 kg-m, 9.5 ft. lbs.)
2. Place bearing outer races on their respective bearings.
Used left and right outer races are not interchangeable and install case assembly in carrier.
3. Install side bearing adjusters on their respective carrier, making sure adjusters are threaded properly.
4. Align match marks on cap and carrier. Screw in two side bearing cap bolts two or three turns and press down bearing cap by hand.
NOTE: If bearing cap does not fit tightly on carrier, side bearing adjuster is not threaded properly. Reinstall adjuster.
Tighten cap bolts.
Provisional Tightening Torque
(a): 15 Nm (1.5 kg-m, 11.0 ft. lbs.)
5. Install actuator bracket to bearing cap and tighten its bolts to specification.
Tightening Torque
(b): 12 Nm (1.2 kg-m, 8.5 ft. lbs.)
6. Tighten both bearing adjusters so as to obtain specified gear backlash and at the same time, obtain preload of side bearing.
Special Tool
(A): 09930-40120 (Attachment)
(B): 09930-40113 (Rotor holder)
(C): 09900-20701
Bevel gear backlash: 0.13-0.18 mm (O.005-0.007 inch)
NOTE:
^ Be sure to apply measuring tip of dial gauge at right angles to convex side of tooth.
^ Measure at least 4 points on drive bevel gear periphery.
^ As a practical measure following would be recommended to obtain specified backlash and side bearing preload at the same time.
1. Obtain specified backlash by turning both adjusters inward lightly.
2. Tighten both adjusters further by one notch at a time.
7. Measure preload of pinion with spring balance or torque wrench and check composite preload of pinion bearing and side bearing.
Special Tool
(D): 09922-75222
NOTE: Standard preload is shown in graph, which should be read as follows.
Example:
When preload of bevel pinion is 2.6 kg/5.73 lbs., acceptable composite preload of both pinion bearings and side bearings should be between 2.8 and 3.2 kg/6.17 and 7.05 lbs.
- Bearing preload can be checked roughly by using flange holder as shown. In this measurement, holder arm itself will work as balance weight and torque will be replaced with angle. However, flange should be rotated very slowly with hand support so as not to allow over revolution due to inertia.
- Repeat side bearing adjustment until gear backlash and composite bearing preload are compatible within specification, if fall to obtain specified measurements first.
Special Tool
(E): 09922-66020
8. Torque bearing cap bolts to specification and install bearing lock plates.
Tightening Torque
(a): 60 Nm (6.0 kg-m, 43.5 ft. lbs.)
(b): 13 Nm (1.3 kg-m, 9.5 ft. lbs.)
9. As final step, check gear tooth contact as follows.
1. After cleaning tooth surface of 10 bevel gears, paint them with gear marking compound evenly by using brush or sponge etc.
2. Turn gear to bring its painted part in mesh with bevel pinion and turn it back and forth by hand to repeat their contact.
3. Bring painted part up and check contact pattern, referring to chart. If contact pattern is not normal, readjust or replace as necessary according to instruction in chart.
NOTE: Be careful not to turn bevel gear more than one full revolution, for it will hinder accurate check.
10. Upon completion of gear tooth contact check in step 8, caulk flange nut with caulking tool and hammer.
11. Clean mating surfaces of both housing and carrier and apply sealant to housing side evenly.
"A": Sealant 99000-31110
12. With differential assembly installed in housing, position it with 2 reamer bolts and then install other 6 bolts.
13. Torque all bolts to specification.
Tightening Torque for diff. carrier bolts
(a) : 23 Nm (2.3 kg-m, 17.0 ft. lbs.)
14. Install front drive shaft.