Reassembly
ReassemblyJudging 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 in the figure.
CAUTION: Perform press-fitting carefully so as not to tilt outer race.
Differential Case Assembly
1) Install differential gears (3), free axle hub (4) and washers (2) to left case (7).
2) Install left case to right case (1) and tighten screws (8).
3) Put bevel gear (1) on differential case (2) and fasten them with 10 bolts (3) by tightening them to specified torque. Use thread lock cement for 10 bolts (3).
CAUTION: Use of any other bolts than that specified is prohibited.
"A": Thread lock cement 99000-32020
4) Press-fit side bearing (1) with special tool and press.
5) Install actuator (1) to differential case (2).
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.
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 below. Shown in the figure of Step 4 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 (1) 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 (2) or torque wrench (3), check for rotation by hand and apply small amount of oil to bearings.
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).
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.
4) Obtain adjusting shim thickness by using measured value by dial gauge (which represents "c" in figure) in following equation.
94 in above equation is "a" + "b" of mounting dummy (special tool) as shown in figure.
5) Select adjusting shim(s) (2) closest to calculated value from among the following available sizes and put it in place and then press-fit front bearing (1).
6) With new pinion spacer (3) inserted as shown, install rear bearing (5) to differential carrier (4).
NOTE:
^ Make sure to use new spacer for reinstallation.
^ Apply oil to bearings.
7) Using special tool and plastic hammer drive oil seal (2) into differential carrier (1) till it becomes flush with carrier end. Then apply grease to oil seal lip.
8) While tightening flange nut gradually with flange holder (special tool) and power wrench (4-10 magnification) (1), set preload of pinion to specification.
NOTE:
^ Before taking measurement with spring balance (3) or torque wrench (4), 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.
^ Be sure to tighten gradually and carefully till specified starting torque is obtained. Turning back overtightened flange nuts should be avoided.
Assembling Unit
1) Apply sealant "A" to thread part of air inlet union (2) and install it to differential carrier (1). Tighten it to specified torque
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 (1) 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.
5) Tighten cap bolts to provisional torque below.
Tightening torque
Side bearing cap bolt (provisional torque) (a): 15 Nm (1.5 kgf-m, 11.0 ft. lbs.)
6) Install actuator bracket to bearing cap and tighten its bolts to specification.
7) Tighten both bearing adjusters (1) so as to obtain specified gear backlash and at the same time, obtain preload of side bearing.
NOTE:
^ Be sure to apply measuring tip of dial gauge (1) at right angles to convex side of tooth.
^ Measure at least 4 points on drive bevel gear periphery.
^ As a practical measure the 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.
8) Measure preload of pinion with spring balance (1) or torque wrench (2) and check composite preload of pinion bearing and side bearing.
NOTE:
^ Standard preload is shown in graph on next page, which should be read as follows.
Example: When preload of bevel pinion is 2.6 kg / 5.73 lb, acceptable composite preload of both pinion bearings and side bearings should be between 2.8 and 3.2 kg / 6.17 and 7.05 lb.
^ Bearing preload can be checked roughly by using flange holder as shown in figure. 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 fail to obtain specified measurements first.
9) Torque bearing cap bolts to specification and install bearing lock plates.
10) 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 the following 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.
11) Upon completion of gear tooth contact check in Step 10), caulk flange nut (2) with caulking tool (1) and hammer.
12) Clean mating surfaces of both housing and carrier and apply sealant "A" to housing side evenly.
13) With differential assembly installed in housing, position it with 2 reamer bolts (2) and then install other 6 bolts (1).
14) Torque all bolts to specification.
15) Install front drive shaft.