Rear Differential: Assembly

Precautions for assembling
- Assemble in the reverse order of disassembling.
- Check and adjust each part during assembly.
- For correct installation, keep the shims and washers in order.
- Thoroughly clean the surfaces on which the shims, washers and bearings are to be installed.
- Apply gear oil when installing the bearings and thrust washers.
- Be careful not to mix up the right and left hand races of the bearings.
- Replace the oil seal with new one at every disassembly. Apply chassis grease between the lips when installing the oil seal.
Fig 1: Applying Chassis Grease Between Lips
Courtesy of SUBARU OF AMERICA, INC.
Adjusting preload for front and rear bearings Adjust the bearing preload with spacer and washer between front and rear bearings. Pinion height adjusting washer are not affected by this adjustment. The adjustment must be carried out without oil seal inserted.
1. Press rear bearing race into differential carrier with ST1 and ST2.
  ST1 398477701 HANDLE
  
  ST2 398477703 DRIFT 2
  
  Fig 2: Pressing Rear Bearing Race Into Differential Carrier
  Courtesy of SUBARU OF AMERICA, INC.
2. Insert ST1 into carrier with pinion height adjusting washer and rear bearing cone fitted onto it.
  CAUTION:
  - Re-use the used washer if not deformed.
  - Use a new rear bearing cone.
3. Then install preload adjusting spacer and washer, front bearing cone, ST2, companion flange, and washer and drive pinion nut.
  ST1 398507702 DUMMY SHAFT
  
  ST2 398507703 DUMMY COLLAR
  
  Fig 3: Identifying Pinion Height Adjusting Shim
  Courtesy of SUBARU OF AMERICA, INC.
4. Turn ST1 with hand to make it seated, and tighten drive pinion nut while measuring the preload with spring balance. Select preload adjusting washer and spacer so that the specified preload is obtained when nut is tightened to the specified torque.
CAUTION: Use a new lock nut.
NOTE:
- Be careful not to give excessive preload.
- When tightening the drive pinion nut, lock ST1 with ST2 as shown in the figure.
ST1 398507704 BLOCK

ST2 398507702 DUMMY SHAFT

Tightening torque:
1. 181 N.m (18.5 kgf-m, 134 ft-lb)
Fig 4: Identifying Block
Courtesy of SUBARU OF AMERICA, INC.

Fig 5: Identifying Specification Torque
Courtesy of SUBARU OF AMERICA, INC.

Fig 6: Identifying Rear Differential Assembly
Courtesy of SUBARU OF AMERICA, INC.

Fig 7: Identifying Dimension Of Preload Adjusting Washer
Courtesy of SUBARU OF AMERICA, INC.

Adjusting drive pinion height

Adjust drive pinion height with shim installed between rear bearing cone and the back of pinion gear.

Install ST1, ST2 and ST3, as shown in the figure, and apply the specified preload on the bearings.

Fig 8: Torque Specifications Table
Courtesy of SUBARU OF AMERICA, INC.

Adjusting preload for front and rear bearings

NOTE: At this time, install a pinion height adjusting shim which is temporarily selected or the same as that used before. Measure and record the thickness.

ST1 398507702 DUMMY SHAFT

ST2 398507701 GAUGE

ST3 398507703 DUMMY COLLAR

Fig 9: Identifying Pinion Height Adjusting Shim
Courtesy of SUBARU OF AMERICA, INC.
Measure the clearance N between the end of ST2 and the end surface of ST1 by using a thickness gauge.
NOTE: Make sure there is no clearance between the case and ST2.

ST1 398507702 DUMMY SHAFT

ST2 398507701 GAUGE

Fig 10: Identifying Dummy Shaft
Courtesy of SUBARU OF AMERICA, INC.

Obtain the thickness of pinion height adjusting shim to be inserted from the following formula, and replace the temporarily installed shim with this one.

T = To + N - (H x 0.01) - 0.20 mm (0.0079 in)

NOTE: Use copies of this page.

Fig 11: Torque Specifications Table

Courtesy of SUBARU OF AMERICA, INC.

(Example of calculation)

To = 2.20 + 1.20 = 3.40 mm
N = 0.23 mm H = + 1,
T = 3.40 + 0.23 - 0.01 - 0.20 = 3.42
Result: Thickness = 3.42 mm

Therefore use the shim 383605200.

PINION HEIGHT ADJUSTING SHIM CHART

Pinion height adjusting shim
Part No.	Thickness mm (in)
383495200	3.09 (0.1217)
383505200	3.12 (0.1228)
383515200	3.15 (0.1240)
383525200	3.18 (0.1252)
383535200	3.21 (0.1264)
383545200	3.24 (0.1276)
383555200	3.27 (0.1287)
383565200	3.30 (0.1299)
383575200	3.33 (0.1311)
383585200	3.36 (0.1323)
383595200	3.39 (0.1335)
383605200	3.42 (0.1346)
383615200	3.45 (0.1358)
383625200	3.48 (0.1370)
383635200	3.51 (0.1382)
383645200	3.54 (0.1394)
383655200	3.57 (0.1406)
383665200	3.60 (0.1417)
383675200	3.63 (0.1429)
383685200	3.66 (0.1441)

Fig 12: Installing Selected Pinion Height Adjusting Shim On Drive Pinion

Courtesy of SUBARU OF AMERICA, INC.

Install the selected pinion height adjusting shim on drive pinion, and press the rear bearing cone into position with ST.
ST 398177700 INSTALLER

Fig 13: Identifying Drive Pinion, Bearing Adjusting Spacer, Washer & Differential Carrier

Courtesy of SUBARU OF AMERICA, INC.

Insert drive pinion into differential carrier, install the previously selected bearing preload adjusting spacer and washer.

Fig 14: Press-fitting Front Bearing Cone Into Case With ST1, ST2 & ST3

Courtesy of SUBARU OF AMERICA, INC.

Press-fit front bearing cone into case with ST1, ST2 and ST3.
ST1 398507703 DUMMY COLLAR

ST2 399780104 WEIGHT

ST3 899580100 INSTALLER

Fig 15: Press-fitting Pilot Bearing With ST1 & ST2

Courtesy of SUBARU OF AMERICA, INC.

Insert spacer, then press-fit pilot bearing with ST1 and ST2.
ST1 399780104 WEIGHT

ST2 899580100 INSTALLER
Fit a new oil seal with ST.
NOTE:
- Press-fit until end of oil seal is 1 mm (0.04 in) inward from end of carrier.
- Apply grease between the oil seal lips.
ST 498447120 INSTALLER

Fig 16: Fitting New Oil Seal With ST

Courtesy of SUBARU OF AMERICA, INC.

Press-fit companion flange with ST1 and ST2.
CAUTION: Be careful not to damage bearing.

ST1 899874100 INSTALLER

ST2 399780104 WEIGHT

Fig 17: Press-fitting Companion Flange With ST1 & ST2

Courtesy of SUBARU OF AMERICA, INC.

Install self-locking nut. Then tighten it with ST.
ST 498427200 FLANGE WRENCH

Tightening torque:
1. 181 N.m (18.5 kgf-m, 134 ft-lb)

Fig 18: Installing Self-Locking Nut Then Tighten It With ST

Courtesy of SUBARU OF AMERICA, INC.

Assembling differential case Install side gears and pinion mate gears, with their thrust washers and pinion mate shaft, into differential case.
CAUTION:
- Apply gear oil on both sides of the washer and on the side gear shaft before installing.
- Insert the pinion mate shaft into the differential case by aligning the lock pin holes.
1. Measure the side gear backlash.
  Side gear back clearance:
  1. 0.10-0.20 mm (0.0039-0.0079 in)
2. Adjust the backlash as specified by selecting side gear thrust washer.
3. Check the condition of rotation after applying oil to the gear tooth surfaces and thrust surfaces.
4. After inserting pinion shaft lock pin into differential case, stake the both sides of the hole to prevent pin from falling off.
Install crown gear on differential case.
CAUTION: Before installing bolts, apply Lock Tite to bolt threads.

Lock Tite:
1. THREE BOND 1324 or equivalent
NOTE: Tighten diagonally while tapping the bolt heads.

Tightening torque:
1. 103 N.m (10.5 kgf-m, 76 ft-lb)

Fig 22: Installing Crown Gear On Differential Case

Courtesy of SUBARU OF AMERICA, INC.

Press side bearing cone onto differential case with ST.
ST 398487700 DRIFT

Fig 23: Pressing Side Bearing Cone Onto Differential Case With ST

Courtesy of SUBARU OF AMERICA, INC.

Adjusting side bearing retainer shims

The driven gear backlash and side bearing preload can be determined by the side bearing retainer shim thickness.
Install the differential case assembly into differential carrier in the reverse order of disassembly.

Fig 24: Adjusting Side Bearing Retainer Shims

Courtesy of SUBARU OF AMERICA, INC.

Install side retainer shims and O-rings to the left and right retainers from which they were removed.

NOTE:

Replace broken or cracked O-ring with new one.
Replace broken or corroded side retainer shim with new one of same thickness.

TORQUE SPECIFICATION CHART

Side bearing retainer shim
Part No.	Thickness mm (in)
383475201	0.20 (0.0079)
383475202	0.25 (0.0098)
383475203	0.30 (0.0118)
383475204	0.40 (0.0157)
383475205	0.50 (0.0197)

Align arrow marked on differential carrier with that marked on side retainer during installation.
CAUTION: Be careful that side bearing outer race is not damaged by bearing roller.

Fig 25: Aligning Arrow Marked On Differential Carrier With That Marked on Side Retainer

Courtesy of SUBARU OF AMERICA, INC.

Tighten side bearing retainer bolts.
CAUTION: Before tightening the two side bearing retainer bolts, apply Lock Tite to bolt threads.

Lock Tite:
1. THREE BOND 1105 or equivalent
Tightening torque:
1. 10.3 N.m (1.05 kgf-m, 7.6 ft-lb)

Fig 26: Tightening Side Bearing Retainer Bolts

Courtesy of SUBARU OF AMERICA, INC.

Measure the crown gear-to-drive pinion backlash. Set magnet base on differential carrier. Align contact point of dial gauge with tooth face of crown gear, and move crown gear while holding drive pinion still. Read value indicated on dial gauge.
Backlash:
1. 0.10-0.20 mm (0.0039-0.0079 in)
At the same time, measure the turning resistance of drive pinion. Compared with the resistance when differential case is not installed, if the increase of the resistance is not within the specified range, readjust side bearing retainer shims.
Turning resistance increase:
1. 2.9-10.8 N (0.3-1.1 kgf, 0.7-2.4 lb)

Fig 27: Measuring Crown Gear-To-Drive Pinion Backlash

Courtesy of SUBARU OF AMERICA, INC.

Re-check crown gear-to-pinion backlash.
Backlash:
1. 0.10-0.20 mm (0.0039-0.0079 in)

Fig 28: Checking Crown Gear-To-Pinion Backlash

Courtesy of SUBARU OF AMERICA, INC.

Check the crown gear runout on its back surface, and make sure pinion and crown gear rotate smoothly.
Limit of runout:
1. Less than 0.05 mm (0.0020 in)

Fig 29: Checking Crown Gear Runout

Courtesy of SUBARU OF AMERICA, INC.

Checking and adjusting tooth contact of crown gear
1. Apply an even coat of red lead on both sides of three or four teeth on the crown gear. Check the contact pattern after rotating crown gear several revolutions back and forth until a definite contact pattern appears on the crown gear.
2. When the contact pattern is incorrect, readjust according to the instructions given in "TOOTH CONTACT PATTERN".
NOTE: Be sure to wipe off red lead completely after adjustment is completed.
If proper tooth contact is not obtained, once again adjust the drive pinion height changing RH and LH side bearing retainer shims and the hypoid gear backlash.
1. Drive pinion height
  ST1 398507702 DUMMY SHAFT
  
  ST2 398507701 GAUGE
  
  Fig 30: Identifying Dummy Shaft
  Courtesy of SUBARU OF AMERICA, INC.
  
  T = To + N - (H x 0.01) - 0.20 (mm)
  
  Where:
  
  T = Thickness of pinion height adjusting shim (mm)
  
  To = Thickness of shim temporarily inserted (mm)
  
  N = Reading of thickness gauge (mm)
  
  H = Figure marked on drive pinion head
2. Hypoid gear backlash
  Backlash:
  1. 0.10-0.20 mm (0.0039-0.0079 in)
  Fig 31: Checking Hypoid Gear Backlash
  Courtesy of SUBARU OF AMERICA, INC.
Fig 32: Identifying Tooth Contact Pattern Chart
Courtesy of SUBARU OF AMERICA, INC.
Install rear cover and tighten bolts to specified torque.
CAUTION: Securely connect ground terminal of rear differential temperature sensor.

Tightening torque:
1. 29 N.m (3.0 kgf-m, 21.7 ft-lb)

Fig 33: Installing Rear Cover Bolts

Courtesy of SUBARU OF AMERICA, INC.