Rear Differential: Assembly

1. Install the rear bearing race into the differential carrier using ST1 and ST2.

   ST1 398477701 HANDLE

   ST2 398477703 DRIFT 2

   Fig 2: Installing Rear Bearing Race Into Differential Carrier Using ST1 And ST2

   Courtesy of SUBARU OF AMERICA, INC.
2. Install the front bearing race to the differential carrier using ST1 and ST2.

   ST1 398477701 HANDLE

   ST2 398477702 DRIFT

3. Insert the ST1 into carrier with the pinion height adjusting washer and rear bearing cone fitted onto it.
   NOTE:

   • If tooth contact (drive pinion, hypoid driven gear) is normal in the inspection before disassembling, verify that the washer is not deformed, and then reuse the used washer.
   • Use new rear bearing cone.
4. Install the preload adjusting spacer and washer, front bearing cone, ST2, companion flange and self-locking nut.

   ST1 398507702 DUMMY SHAFT

   ST2 398507703 DUMMY COLLAR

   Fig 3: Installing Preload Adjusting Spacer

   Courtesy of SUBARU OF AMERICA, INC.
5. Turn the ST1 by hand to smooth the bearing, and tighten the self-locking nut while measuring the initial load or initial torque with a spring scale or torque wrench. Select the preload adjusting washer and spacer so that the specified preload is obtained when nut is tightened to the specified torque.
   NOTE:

   • Use a new self-locking nut.
   • Measure the preload in direction of tangent to the flange.
   • Be careful not to give excessive preload.
   • When tightening the self-locking nut, lock ST1 with ST2 as shown in the illustration.

   ST1 398507702 DUMMY SHAFT

   ST2 398507704 BLOCK

   Tightening torque: 

   181.5 N.m (18.5 kgf-m, 133.9 ft-lb) 

   Fig 4: Tightening Self-Locking Nut

   Courtesy of SUBARU OF AMERICA, INC.

   Initial load: 

   18.1 - 38.8 N (1.8 - 4.0 kgf, 4.1 - 8.7 lb) 

   Fig 5: Measuring Preload Of Self-Locking Nut

   Courtesy of SUBARU OF AMERICA, INC.

   Initial torque: 

   0.69 - 1.47 N.m (0.07 - 0.15 kgf-m, 0.51 - 1.08 ft-lb) 

   Fig 6: Checking Initial Torque Of Self-Locking Nut

   Courtesy of SUBARU OF AMERICA, INC.
   PARTS THICKNESS CHART
   
   

   Preload adjusting washer
   Part No.	Thickness mm (in)
   383705200	2.59 (0.1020)
   383715200	2.57 (0.1012)
   383725200	2.55 (0.1004)
   383735200	2.53 (0.0996)
   383745200	2.51 (0.0988)
   383755200	2.49 (0.0980)
   383765200	2.47 (0.0972)
   383775200	2.45 (0.0965)
   383785200	2.43 (0.0957)
   383795200	2.41 (0.0949)
   383805200	2.39 (0.0941)
   383815200	2.37 (0.0933)
   383825200	2.35 (0.0925)
   383835200	2.33 (0.0917)
   383845200	2.31 (0.0909)

   PARTS SPECIFICATION CHART
   
   

   Preload adjusting spacer
   Part No.	Length mm (in)
   383695201	56.2 (2.213)
   383695202	56.4 (2.220)
   383695203	56.6 (2.228)
   383695204	56.8 (2.236)
   383695205	57.0 (2.244)
   383695206	57.2 (2.252)

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

1. Attach the ST2.
   NOTE: At this time, install a provisionally selected or previously used pinion height adjusting washer. Measure and record the thickness.

   ST1 398507702 DUMMY SHAFT

   ST2 398507701 DIFFERENTIAL CARRIER GAUGE

   ST3 398507703 DUMMY COLLAR

   Fig 7: Measuring Clearance "N" Between End Of ST2 And End Surface Of ST1

   Courtesy of SUBARU OF AMERICA, INC.
2. 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 DIFFERENTIAL CARRIER GAUGE

   Fig 8: Measuring Clearance "N" Between End Of ST2 And End Surface Of ST1 Using Thickness Gauge

   Courtesy of SUBARU OF AMERICA, INC.
3. Obtain the thickness of pinion height adjusting washer to be inserted from the following formula, and replace the temporarily installed washer with this one.

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

   NOTE: Use copies of this page.
   PARTS THICKNESS CHART
   
   

   T	Thickness of pinion height adjusting washer mm (in)
   To	Thickness of washer temporarily inserted mm (in)
   N	Clearance of thickness gauge mm (in)
   H	illustration marked on drive pinion head
   Memo:

   (Example of calculation)

   To = 3.39 mm (0.1335 in)

   N = 0.24 mm (0.0094 in)

   H = + 1

   T = 3.39 mm (0.1335 in) + 0.24 mm (0.0094 in) - 0.01 mm (0.0004 in) - 0.20 mm (0.0079 in) = 3.42 mm (0.1346 in)

   Result: Thickness = 3.42 mm (0.1346 in)

   Therefore use washer 383605200.

   PARTS THICKNESS CHART
   
   

   Pinion height adjusting washer
   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)

ST 398177700 INSTALLER

Fig 9: Installing Selected Pinion Height Adjusting Washer On Drive Pinion

Courtesy of SUBARU OF AMERICA, INC.

ST1 398507703 DUMMY COLLAR

ST2 399780104 WEIGHT

ST3 899580100 INSTALLER

Fig 11: Pressing Front Bearing Cone Into Case With ST1, ST2 And ST3

Courtesy of SUBARU OF AMERICA, INC.

ST1 399780104 WEIGHT

ST2 899580100 INSTALLER

Fig 12: Pressing Pilot Bearing With ST1 And ST2

Courtesy of SUBARU OF AMERICA, INC.

ST1 899874100 INSTALLER

ST2 399780104 WEIGHT

Fig 14: Pressing Companion Flange With ST1 And ST2

Courtesy of SUBARU OF AMERICA, INC.

Seal material: 

THREE BOND 1324 (Part No. 004403042) or equivalent 

Tightening torque: 

181.5 N.m (18.5 kgf-m, 133.9 ft-lb) 

ST 498427200 FLANGE WRENCH

Fig 15: Tightening Self-Locking Nut

Courtesy of SUBARU OF AMERICA, INC.

Initial load: 

18.1 - 38.8 N (1.8 - 4.0 kgf, 4.1 - 8.7 lbf) 

Fig 16: Measuring Preload Of Self-Locking Nut

Courtesy of SUBARU OF AMERICA, INC.

Initial torque: 

0.67 - 7.47 N.m (0.07 - 0.15 kgf-m, 0.49 - 1.08 ft-lb) 

Fig 17: Checking Initial Torque Of Self-Locking Nut

Courtesy of SUBARU OF AMERICA, INC.

Install the side gears and pinion mate gears, with their thrust washers, pinion mate gear washer, and pinion mate shaft, into the differential case.

1. Measure the side gear backlash.

   Side gear backlash: 

   0.10 - 0.20 mm (0.004 - 0.008 in) 

   Fig 19: Measuring Side Gear Backlash

   Courtesy of SUBARU OF AMERICA, INC.
2. Adjust the backlash as specified by selecting side gear thrust washer.
   PARTS THICKNESS CHART
   
   

   Side gear thrust washer
   Part No.	Thickness mm (in)
   383445201	0.75 - 0.80 (0.0295 - 0.0315)
   383445202	0.80 - 0.85 (0.0315 - 0.0335)
   383445203	0.85 - 0.90 (0.0335 - 0.0354)

3. Check the condition of rotation after applying differential gear oil to the gear tooth surfaces and thrust washer surfaces.
4. Drive the pinion shaft lock pin into the differential case.

ST 398487700 DRIFT

Fig 21: Pressing Side Bearing To Differential Case Using ST

Courtesy of SUBARU OF AMERICA, INC.

1. Using the ST, press-fit the side bearing race to the side retainer.

   ST 398417700 DRIFT

   Fig 22: Pressing Side Bearing Outer Race To Side Retainer Using ST

   Courtesy of SUBARU OF AMERICA, INC.
2. Install the oil seal. < Ref. to REPLACEMENT , Rear Differential Side Oil Seal. >

1. The hypoid driven gear backlash and side bearing preload can be adjusted by the side retainer shim thickness.
2. Install the differential case assembly into differential carrier in the reverse order of disassembly.
   NOTE: Be careful not to hit the teeth of hypoid driven gear against the differential carrier.
   Fig 23: Installing Differential Case Assembly Into Differential Carrier

   Courtesy of SUBARU OF AMERICA, INC.
3. Install the side retainer shim and O-ring.
   NOTE:

   • Use new O-rings.
   • Be careful not to mix up the side retainer shim RH and LH.
   • Replace broken or corroded side retainer shims with a new part of the same thickness.
   PARTS THICKNESS CHART
   
   

   Side 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)

4. Align the arrow mark on the differential carrier with the arrow mark on the side retainer when installing the side retainer.
   NOTE: Be careful that the side bearing outer race is not damaged by the bearing roller.
   Fig 24: Alignment Mark On Differential Carrier And Side Retainer

   Courtesy of SUBARU OF AMERICA, INC.
5. Tighten the side retainer bolts.

   Tightening torque: 

   10.5 N.m (1.1 kgf-m, 7.7 ft-lb) 

   Fig 25: Locating Side Retainer Bolts

   Courtesy of SUBARU OF AMERICA, INC.
6. Measure the hypoid driven gear to drive pinion backlash. Set the magnet base on differential carrier. Align the contact point of dial gauge with tooth face of hypoid driven gear, and move hypoid driven gear while holding drive pinion still. Read the value indicated on dial gauge. If the backlash is outside the standard range, adjust the side retainer shim by the following method.
   • When backlash is less than 0.1 mm (0.004 in): 

     Reduce the thickness of shim on the back side of the hypoid driven gear and increase the thickness of shims on the teeth side of the hypoid driven gear.

   • When backlash exceeds 0.2 mm (0.008 in): 

     Increase the thickness of shim on the back side of the hypoid driven gear and reduce the thickness of shims on the teeth side of the hypoid driven gear.

   Backlash: 

   0.10 - 0.20 mm (0.004 - 0.008 in) 

   Fig 26: Measuring Hypoid Driven Gear To Drive Pinion Backlash

   Courtesy of SUBARU OF AMERICA, INC.
7. Measure the total preload of the drive pinion. If the total preload is not within specification, adjust the thickness of side retainer shims, increasing/reducing both shims by an even amount at a time.

   Total preload: 

   20.7 - 54.4 N (2.1 - 5.5 kgf, 4.7 - 12.2 lbf) 

Backlash: 

0.10 - 0.20 mm (0.004 - 0.008 in) 

Fig 27: Measuring Hypoid Driven Gear To Drive Pinion Backlash

Courtesy of SUBARU OF AMERICA, INC.

Hypoid driven gear back surface runout: 

0.05 mm (0.002 in) 

Fig 28: Checking Back Side Of Hypoid Driven Gear Runout

Courtesy of SUBARU OF AMERICA, INC.

1. Apply lead-free red dye evenly on the both sides of three to four teeth of the hypoid driven gear. Check the contact pattern after rotating the hypoid driven gear several revolutions back and forth until a definite contact pattern appears on the hypoid driven gear.
2. When the contact pattern is not correct, adjust.
   NOTE: Be sure to wipe off the lead-free red dye completely after the adjustment is completed.
   • Correct tooth contact

     Check item: Tooth contact pattern is slightly shifted toward toe side under no-load rotation. (When driving, it moves towards the heel side.) 

     Fig 29: Toe And Heel Side Tooth Contact Pattern

     Courtesy of SUBARU OF AMERICA, INC.
   • Face contact

     Check item: Backlash is too large. 

     Contact pattern

     Fig 30: Face Contact Pattern

     Courtesy of SUBARU OF AMERICA, INC.

     Corrective action: Reduce the thickness of pinion height adjusting washer according to the procedure for bringing drive pinion away from hypoid driven gear.

     Fig 31: Adjusting Drive Pinion Height

     Courtesy of SUBARU OF AMERICA, INC.
   • Flank contact

     Check item: Backlash is too small. 

     Contact pattern

     Fig 32: Flank Contact Pattern

     Courtesy of SUBARU OF AMERICA, INC.

     Corrective action: Increase thickness of pinion height adjusting washer according to the procedure for bringing drive pinion close to hypoid driven gear side.

     Fig 33: Adjusting Drive Pinion Height

     Courtesy of SUBARU OF AMERICA, INC.
   • Toe contact (inside contact)

     Check item: Teeth contact area is too small. 

     Contact pattern

     Fig 34: Toe Contact Pattern (Inside Contact)

     Courtesy of SUBARU OF AMERICA, INC.

     Corrective action: Reduce the thickness of pinion height adjusting washer according to the procedure for bringing drive pinion away from hypoid driven gear.

     Fig 35: Adjusting Drive Pinion Height

     Courtesy of SUBARU OF AMERICA, INC.
   • Heel contact (outside end contact)

     Check item: Teeth contact area is too small. 

     Contact pattern

     Fig 36: Heel Contact Pattern (Outside End Contact)

     Courtesy of SUBARU OF AMERICA, INC.

     Corrective action: Increase thickness of pinion height adjusting washer according to the procedure for bringing drive pinion close to hypoid driven gear side.

     Fig 37: Adjusting Drive Pinion Height

     Courtesy of SUBARU OF AMERICA, INC.

1. Drive pinion height

   ST1 398507702 DUMMY SHAFT

   ST2 398507701 DIFFERENTIAL CARRIER GAUGE

   Fig 38: Adjusting Drive Pinion Height

   Courtesy of SUBARU OF AMERICA, INC.

   T = To + N - (H x 0.01) - 0.20 mm (0.008 in)

   PARTS THICKNESS CHART
   
   

   T	Thickness of pinion height adjusting washer mm (in)
   To	Thickness of washer temporarily inserted mm (in)
   N	Clearance of thickness gauge mm (in)
   H	illustration marked on drive pinion head

2. Hypoid gear backlash

   Backlash: 

   0.10 - 0.20 mm (0.004 - 0.008 in) 

   Fig 39: Measuring Hypoid Driven Gear To Drive Pinion Backlash

   Courtesy of SUBARU OF AMERICA, INC.

Liquid gasket: 

THREE BOND 1110B (Part No. K0879Y0020) or equivalent 

Tightening torque: 

10.5 N.m (1.1 kgf-m, 7.7 ft-lb) 

Fig 41: Locating Side Retainer Bolts

Courtesy of SUBARU OF AMERICA, INC.

Tightening torque: 

29.5 N.m (3.0 kgf-m, 21.8 ft-lb) 

Fig 42: Gasket And Rear Cover With Bolts

Courtesy of SUBARU OF AMERICA, INC.

Liquid gasket: 

THREE BOND 1105 (Part No. 004403010) or equivalent 

Tightening torque: 

49 N.m (5.0 kgf-m, 36.1 ft-lb)