Nissan Pick-ups and Pathfinder 1989-1995

Differential

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OVERHAUL



Model R180A

See Figure 1

DISASSEMBLY

Final Drive Housing

  1. Remove the final drive unit and mount it in a vise.
  2.  
  3. Remove the 4 bolts and pull off the extension tube and differential side shaft assembly.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the front final drive-R180A

  1. While holding the side flange from rotating, loosen the flange retaining nut and then remove the side flange.
  2.  
  3. Mark the side retainers and remove them; be careful not to mix the left or right retainers and shims.
  4.  
  5. Lift the differential case out of the housing.
  6.  
  7. Using a gear puller (ST33290001, or equivalent), remove the side outer races and then remove the side oil seal. Make sure that you keep the side bearing outer races together with their respective inner cones. Don't mix them up!
  8.  
  9. Loosen the drive pinion nut with a flange wrench and then remove the companion flange with a gear puller.
  10.  
  11. Using a brass drift, press out the drive pinion together with the pinion rear bearing inner cone, the drive pinion bearing spacer and the pinion bearing adjusting washer.
  12.  
  13. Using a brass drift again, remove the pinion front and rear bearing outer races.
  14.  
  15. Press out the pinion rear bearing inner cone and the drive pinion adjusting washer.
  16.  

Differential Case
  1. Remove the side bearing inner cones with a puller. Be sure that the puller arms engage the grooves and also make sure that you identify each cone.
  2.  
  3. Loosen the ring gear bolts in a crisscross pattern.
  4.  
  5. Use a rubber mallet and carefully tap the ring gear off of the differential case.
  6.  
  7. Matchmark the case halves and then separate the differential cases.
  8.  

Extension Tube and Differential Side Shaft
  1. Use a rubber mallet and knock (carefully!) the side shaft out of the extension tube.
  2.  
  3. Cut the rear axle bearing collar with a cold chisel, but be sure you don't damage the side shaft.
  4.  
  5. Reinstall the side shaft into the extension tube and secure it with bolts. Remove the rear axle bearing by pulling out the side shaft with a puller.
  6.  
  7. Remove the grease seal.
  8.  

INSPECTION

Check the teeth on the ring gear and drive pinion for scoring, cracking or chipping. if any damaged parts are evident, replace the gear and pinion as a set (hypoid gear set).

Check the mating surfaces of the differential case, side gears, pinion mate gears, pinion mate shaft and thrust washers.

Clean the bearing thoroughly and check for any wear, scratches, pitting of flaking. Check the roller bearing for smooth rotation. If any damage can be detected, replace the outer race and inner cone as a set.

ASSEMBLYExtension Tube and Differential Side Shaft
  1. Measure the rear axle bearing end-play. It should be 0.039 in. (1.0mm) or less. End-play is adjusted with shims.
  2.  
  3. Install the grease seal.
  4.  
  5. Install the extension tube retainer, rear axle bearing and the rear axle shaft bearing collar on the side shaft.
  6.  
  7. Install the side shaft assembly into the extension tube.
  8.  

Differential Case
  1. Measure the clearance between the side gear thrust washer and the differential case. It should be 0.0039-0.0079 in. (0.1-0.2mm). Clearance can be adjusted with new side gear thrust washers.
  2.  
  3. Coat the tooth and thrust surfaces with gear oil and check that they turn properly.
  4.  
  5. Install the differential case halves.
  6.  
  7. Position the case on the ring gear. Coat the ring gear bolts with a locking agent compound and then install them. Tighten them in a crisscross pattern, lightly tapping each bolt head with a hammer.
  8.  
  9. Press the side bearing inner cones onto the differential case.
  10.  

Final Drive Housing
  1. Press the front and rear bearing outer races into the housing.
  2.  
  3. Install the pinion bearing adjustment washer and the drive pinion bearing spacer.
  4.  
  5. Install the drive pinion height adjusting washer into the drive pinion and then press in the pinion rear bearing inner cone.
  6.  
  7. Position the pinion front bearing inner cone into the final drive. Coat the oil seal lip cavity with grease, then install the seal into the housing.
  8.  
  9. Position the bearing spacer, adjusting washer and drive pinion in the housing, then insert the companion flange into the drive pinion by tapping it lightly with a mallet.
  10.  
  11. Clean the pinion threads and nut threads and tighten the pinion retaining nut.
  12.  
  13. Rotate the drive pinion several times in each direction, then measure bearing preload. It should be 7.8-14.8 inch lbs. (0.9-1.7 Nm). Adjust preload by changing the thickness of the adjusting washer and spacer.
  14.  
  15. Install the side retainer adjusting shim and then press in the side bearing outer race.
  16.  
  17. Install the side oil seal.
  18.  
  19. Install the differential case assembly.
  20.  
  21. Position the side retainer adjusting shims and the O-ring on the side retainer, then install them in the final drive. Make sure that the arrows stamped on the side retainer are aligned.
  22.  
  23. Using a dial indicator, check the ring gear-to-drive pinion backlash. It should be 0.0051-0.0071 in. (0.13-0.18mm). If backlash is too small, decrease the thickness of the right shim and increase the thickness of the left shim by the same amount. If backlash is too great, increase the thickness of the right shim and decrease the thickness of the left shim by the same amount. Never change the total amount of the shims as it will change the bearing preload.
  24.  
  25. Check total preload and ring gear run-out.
  26.  
  27. Install the rear cover and gasket.
  28.  
  29. Install the extension tube and side shaft assembly.
  30.  

Model R200A

See Figure 2

DISASSEMBLYFinal Drive Housing
  1. Remove the final drive unit and mount it in a vise.
  2.  
  3. Remove the differential side shaft assembly.
  4.  



Click image to see an enlarged view

Fig. Fig. 2: Exploded view of the front final drive-R200A

  1. While holding the side flange from rotating, loosen the flange retaining nut and then remove the side flange.
  2.  
  3. Mark the side bearing cap and remove it; be careful not to mix the left or right retainers and shims.
  4.  
  5. Lift the differential case out of the housing.
  6.  
  7. Loosen the drive pinion nut with a flange wrench and then remove the companion flange with a gear puller.
  8.  
  9. Using a brass drift, press out the drive pinion together with the pinion rear bearing inner cone, the drive pinion bearing spacer and the pinion bearing adjusting washer.
  10.  
  11. Using a brass drift again, remove the pinion front and rear bearing outer races.
  12.  
  13. Press out the pinion rear bearing inner cone and the drive pinion adjusting washer.
  14.  

Differential Case
  1. Remove the side bearing inner cones with a puller. Be sure that the puller arms engage the grooves and also make sure that you identify each cone.
  2.  
  3. Loosen the ring gear bolts in a crisscross pattern.
  4.  
  5. Use a rubber mallet and carefully tap the ring gear off of the differential case.
  6.  
  7. Punch off the pinion mate shaft lockpin from the ring gear side.
  8.  

Differential Side Shaft
  1. Cut the rear axle bearing collar with a cold chisel, but be sure you don't damage the side shaft.
  2.  
  3. Reinstall the side shaft into the extension tube and secure it with bolts. Remove the rear axle bearing by pulling out the side shaft with a puller.
  4.  
  5. Remove the grease seal and oil seal.
  6.  

INSPECTION

Check the teeth on the ring gear and drive pinion for scoring, cracking or chipping. if any damaged parts are evident, replace the gear and pinion as a set (hypoid gear set).

Check the mating surfaces of the differential case, side gears, pinion mate gears, pinion mate shaft and thrust washers.

Clean the bearing thoroughly and check for any wear, scratches, pitting or flaking. Check the roller bearing for smooth rotation. If any damage can be detected, replace the outer race and inner cone as a set.

ASSEMBLY

Differential Side Shaft

  1. Measure the rear axle bearing end-play. It should be 0.039 in. (1.0mm) or less. End-play is adjusted with shims.
  2.  
  3. Install the oil seal and grease seal.
  4.  
  5. Install the extension tube retainer, rear axle bearing and the rear axle shaft bearing collar on the side shaft.
  6.  

Differential Case
  1. Measure the clearance between the side gear thrust washer and the differential case (subtract B from A ). It should be 0.0039-0.0079 in. (0.1-0.2mm). Clearance can be adjusted with new side gear thrust washers.
  2.  
  3. Coat the tooth and thrust surfaces with gear oil and check that they turn properly.
  4.  
  5. Install the differential case halves.
  6.  
  7. Position the case on the ring gear. Coat the ring gear bolts with a locking agent compound and then install them. Tighten them in a crisscross pattern, lightly tapping each bolt head with a hammer.
  8.  
  9. Press the side bearing inner cones onto the differential case.
  10.  

Final Drive Housing
  1. Press the front and rear bearing outer races into the housing.
  2.  
  3. Install the pinion bearing adjustment washer and the drive pinion bearing spacer.
  4.  
  5. Install the drive pinion height adjusting washer into the drive pinion and then press in the pinion rear bearing inner cone.
  6.  
  7. Position the pinion front bearing inner cone into the final drive. Coat the oil seal lip cavity with grease and then install the seal into the housing.
  8.  
  9. Position the bearing spacer, adjusting washer and drive pinion in the housing and then insert the companion flange into the drive pinion by tapping it lightly with a mallet.
  10.  
  11. Clean the pinion threads and nut threads and tighten the pinion retaining nut.
  12.  
  13. Rotate the drive pinion several times in each direction, then measure bearing preload. It should be 7.8-14.8 inch lbs. (0.9-1.7 Nm). Adjust preload by changing the thickness of the adjusting washer and spacer.
  14.  
  15. Install the side bearing adjusting washer, then install the differential case assembly with the side bearing outer races into the housing.
  16.  
  17. Insert the bearing adjusting washers between the side bearings and the housing.
  18.  
  19. Drive in the side bearing spacer.
  20.  
  21. Align the matchmarks and install the bearing cap.
  22.  
  23. Coat the oil seal lip cavity with grease and install the seal.
  24.  
  25. Using a dial indicator, check the ring gear-to-drive pinion backlash. It should be 0.0051-0.0071 in. (0.13-0.18mm). If backlash is too small, decrease the thickness of the right shim and increase the thickness of the left shim by the same amount. If backlash is too great, increase the thickness of the right shim and decrease the thickness of the left shim by the same amount. Never change the total amount of the shims as it will change the bearing preload.
  26.  
  27. Check total preload and ring gear run-out.
  28.  
  29. Install the rear cover and gasket.
  30.  
  31. Install the extension tube and side shaft assembly.
  32.  

 
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