Assembly
DIFFERENTIAL CASE ASSEMBLYExcept Limited Slip & Rear Differential Lock
1. Install side gear thrust washers and side gears into differential case.
2. Install pinion gears with washers into case. Rotate pinion gears to mesh with side gears.
3. Install pinion shaft. Do not install lockpin at this time.
4. Insert a wedge between side gear and pinion shaft to prevent side gear from turning, then install dial indicator to gear and measure gear backlash. Backlash must not exceed .005 inch on rear differentials, or .006 inch on front differentials. If backlash is not within specifications, replace side gear thrust spacers as needed, then recheck backlash.
5. Align pinion shaft lockpin hole with differential case lockpin hole, then drive lockpin into hole. Stake the lockpin in position in two places, using a punch.
6. Remove adhesive tape from drive gear attaching bolts and the internal threads in gear.
7. Apply Loctite No. 271, or equivalent, to drive gear threaded holes, then install gear onto case with reference marks aligned. Torque attaching bolts alternately, in a diagonal pattern, to 58-65 ft. lbs.
Limited Slip & Rear Differential Lock
Fig. 8 Finding Dimension A. Montero, Pickup & Starion:
Fig. 9 Measuring Plate Thickness. Montero, Pickup & Starion:
Fig. 10 Finding Dimension B. Montero, Pickup & Starion:
1. Measure differential case depth (A), Fig. 8, (A=E - F+G).
2. Measure spring disc and plate thickness, with both extended in the same direction and one placed over the other as shown, Fig. 9. Arrange them so that the difference between left and right is minimized, then measure thicknesses of friction plates and discs in the same manner. Right side (Lr) and left side (Ll).
3. Measure thickness of left and right clutch plate assemblies, then find the difference of the two. Difference should not exceed .002 inch. Clutch plate assembly thickness is thickness of spring, disc, spring plate, friction disc and friction plate.
4. Assemble right and left friction plates, friction discs, pinion shafts and pressure rings, then measure total width (B), Fig. 10. Measure distance between clutch plates on a line with V-shaped groove in the pressure ring while pressing from both sides, ensuring groove is secured against pinion shaft. All parts should be dry.
5. Measure clearance between clutch plate and differential (S), then use the following formula: A(B+Lr+Ll).
6. If the difference (S) between the depth (A) of differential case and the overall width (B) obtained previously, plus the spring plate and spring disc assembly thickness is not within .002-.008 inch, replace friction discs to adjust.
Fig. 27 Finding Thrust Washer Thickness. Montero & Pickup:
Fig. 28 Finding Dimension R:
7. Measure distance (A), Fig. 27, then the depths of thrust washer contact surfaces, dimensions (C) and (D), in differential cases A and B.
8. Assemble pressure rings, pinion gears, side gears, pinion shafts and thrust washers.
9. Measure distance from back of left pressure ring to edge of thrust washer and ensure difference between the two does not exceed .002 inch. Measure distance between clutch plates on a line with V-shaped groove in the pressure ring while pressing from both sides, ensuring groove is secured against pinion shaft. All parts should be dry.
10. Measure overall width shown in Fig. 28, as dimension (R).
11. Using width of assembled differential unit and depth of differential case, measure clearance of side gear in axial direction. If clearance is not .002-.007 inch, replace thrust washers to adjust. Find clearance of side gear in axial direction using formula: A+C+DR.
12. Before assembly, apply lubricant to all contacting surfaces.
Fig. 11 Assembling Differential Clutch Components. Montero, Pickup & Starion:
13. Assemble differential clutch and pinion assembly as shown, Fig. 11.
14. After assembly, measure rotating torque of assembly using tool No. MB990988 or equivalent. Turning torque should be 25-72 ft. lbs., for used clutch plates or 47-72 ft. lbs., for new clutch plates.
15. Remove old adhesive from drive gear attaching bolts, then apply sealer to bolts.
16. Insert and tighten bolts, then alternately torque to 58-65 ft. lbs.
Drive Pinion
1. Press drive front and rear bearing outer races into gear carrier using tools Nos. MB990934, MB990936 and MB990938 or equivalents.
Fig. 5 Measuring Drive Pinion Height:
2. Adjust drive pinion height as follows:
a. Install tool No. MB990819 or equivalent and the drive pinion bearings into gear carrier. Apply a thin coat of grease to washer on tool.
b. Gradually tighten nut on tool until drive pinion preload is 3.5-4.3 inch lbs.
c. Position cylinder of tool No. MB990552 or equivalent, in side bearing seat of gear carrier, Fig. 5.
d. Using a feeler gauge, measure clearance between the two tools, then select drive pinion rear adjusting shim(s) corresponding to this measurement.
e. Install shim(s) between pinion and rear bearing, then press rear bearing onto pinion.
f. If the gear set is being replaced, install new shims of the same thickness as those previously used on the drive pinion. In determining thickness of shim pack to be used, the amount of compression of the shim pack and wear of the bearing, if the old bearing is reused, should be taken into consideration.
3. Adjust drive pinion preload as follows:
a. Install pinion preload adjusting shim between pinion spacer and front bearing. Torque end yoke on rear differentials to 138-180 ft. lbs.; on front differentials to 3.5-4.3 inch lbs. without oil seal installed.
b. Measure drive pinion preload. Preload should measure 3.5-4.3 inch lbs. without oil seal installed.
c. Adjust preload, as necessary, by replacing adjusting shims, or drive pinion spacers.
4. Remove end yoke, then apply a thin coat of grease to lip of oil seal. Drive seal into gear carrier using tool No. MB990031 or equivalent.
5. Apply grease to end yoke mating surface of seal, then install the end yoke. Torque attaching nut to 138-180 ft. lbs., on rear differentials, or 116-159 ft. lbs., on front differentials.
Side Bearing & Drive Gear
1. Install side bearing inner race into differential case using tool No. MB990802 or equivalent.
2. For front differentials, adjust drive gear backlash as follows:
a. Install side bearing adjusting spacers, thinner than those removed, to the side gear bearings, then install differential case assembly into gear carrier. Select adjusting spacers of the same thickness for both the drive pinion side and the drive gear side.
b. Push differential case to one side, then measure clearance between gear carrier and side bearing adjusting space using two feeler gauges.
c. Remove, then measure the thickness of side bearing adjusting spacers from one side.
d. To determine proper thickness spacer to be used, add .002 inch to thickness measured in step c and one-half the clearance measured in step b.
e. Install one pair of the correct spacers each to the drive pinion side and drive gear side.
f. Install differential case assembly, with side bearing adjusting spacers, into gear carrier. Gently tap spacers with a brass drift to seat them on bearing outer race.
g. Install bearing cap with reference marks aligned. Torque cap bolts to 40-47 ft. lbs.
3. For rear differentials, proceed as follows:
a. Position differential case assembly into gear carrier, then install carrier cap and cap nuts. Tighten cap nuts finger tight only.
b. Install side bearing nut to carrier cap, then torque to 40-47 ft. lbs.
c. Install side bearing nut on each side of drive gear using tool No. MB990201 or equivalent, then torque to 11 ft. lbs. Turn bearing nuts in and out several times until they operate smoothly before final tightening.
Fig. 29 Measuring Drive Gear Backlash. Montero, Pickup & Van/Wagon Rear Differential:
d. Measure drive gear backlash, Fig. 29. Backlash should measure .005-.007 inch. If backlash is less than .005 inch, loosen side bearing nut on back side of drive gear and tighten nut on front side of gear by the same amount.
e. When backlash has been adjusted within specifications, tighten both side bearing nuts by a half pitch to preload side bearings. One pitch equals the space between two adjacent holes on the side of the side bearing nuts.
f. Install lock plate, then torque attaching nut to 11-15 ft. lbs.
Fig. 14 Checking Gear Tooth Contact:
Fig. 15 Gear Tooth Contact Pattern Chart:
Fig. 30 Measuring Drive Gear Runout:
4. Check drive gear and drive pinion for proper tooth contact by applying marking compound to both surfaces of drive gear teeth. Insert a brass rod between carrier and case and rotate yoke end by hand one revolution in each direction, Fig. 14, while applying a load of approximately 2 ft. lbs., to the drive pinion. Adjust pinion height and backlash as needed until tooth contact pattern resembles standard pattern, Fig. 15.
5. Measure drive gear runout using dial indicator, Fig. 30. If runout exceeds .002 inch, change position of drive gear in differential and recheck. If runout still exceeds specification, replace drive gear or differential case as needed.