Replace the rear differential pinion seal to stop leaks from the driveshaft entry point on the rear differential housing.

Warnings

Tools required

Parts

• Rear differential pinion seal × 1 — Use OEM specification
• Rear differential gasket or RTV sealant × 1 — Use OEM specification
• Crush washer for pinion nut (if equipped) × 1 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Chock front wheels securely
3. Allow differential to cool completely if vehicle was recently driven
4. Raise rear of vehicle and support on jack stands at manufacturer-specified lift points
5. Verify vehicle is stable before working underneath

Procedure

1. 1

   Access and drain rear differential
   Locate the rear differential drain plug on the bottom of the differential housing. Position drain pan underneath and remove the drain plug using appropriate socket. Allow all gear oil to drain completely (approximately 2 quarts). Inspect drained fluid for metal particles or abnormal debris which may indicate internal damage.
2. 2

   Mark pinion flange position
   Before removing any components, use paint marker to mark the exact rotational position of the pinion flange relative to the pinion shaft. Also count and record the number of exposed threads on the pinion nut. This ensures correct bearing preload is maintained during reassembly.
3. 3

   Remove driveshaft from pinion flange
   Support the rear driveshaft with wire or bungee cord to prevent it from dropping. Remove the four bolts securing the driveshaft U-joint straps to the pinion flange. Carefully lower driveshaft and support it to avoid damaging the center support bearing. Inspect U-joint for wear while accessible.
   ⚠Do not allow driveshaft to hang unsupported as this may damage the center support bearing or transmission output seal.
   Torque spec

   Driveshaft U-Joint Straps20 Nm (15 lb-ft)
4. 4

   Remove pinion nut
   Using the pinion flange holding tool or chain wrench to prevent rotation, remove the pinion nut with a breaker bar and appropriate socket. Note the torque required to turn the pinion (rotational torque) before the nut is completely removed. This value will be needed during reassembly to verify bearing preload.
   ⚠The pinion nut is under high tension. Ensure the holding tool is secure before applying force.
5. 5

   Remove pinion flange
   Remove the pinion flange from the pinion shaft. This may require gentle prying or light tapping with a soft-faced hammer. If resistant, use a proper puller to avoid damaging the pinion shaft threads. Once removed, inspect the flange mating surface for damage or scoring.
6. 6

   Remove old pinion seal
   Using a seal puller or carefully positioned pry bar, extract the old pinion seal from the differential housing. Work carefully to avoid damaging the seal bore in the housing. Clean the seal bore thoroughly with a lint-free cloth and inspect for scoring, pitting, or damage that could cause the new seal to leak.
   ⚠Do not damage the seal bore surface. Scratches or gouges will prevent the new seal from seating properly.
7. 7

   Install new pinion seal
   Lightly coat the outer diameter of the new seal with gear oil. Position the seal squarely in the bore with the seal lip facing inward toward the differential. Using a seal driver or appropriately sized socket that contacts only the outer edge of the seal, carefully drive the seal into the bore until it seats flush with the housing face. Coat the seal lip with clean gear oil.
8. 8

   Reinstall pinion flange
   Clean the pinion shaft and flange splines thoroughly. Apply a light coat of gear oil to the splines and carefully install the pinion flange onto the shaft, aligning with the reference marks made during disassembly. Ensure the flange is fully seated on the shaft.
9. 9

   Install and torque pinion nut
   Install the pinion nut (with new crush washer if equipped). While holding the flange, tighten the pinion nut incrementally. Periodically check the pinion rotational torque with an inch-pound torque wrench. Continue tightening until the pinion nut reaches the same position (thread count) as marked during disassembly AND the rotational torque matches the original specification (typically 10-15 inch-pounds for used bearings). Do not overtighten.
   ⚠️Excessive pinion nut torque will destroy the pinion bearing. Insufficient torque will allow the nut to loosen and cause catastrophic differential failure. Verify bearing preload carefully.
10. 10

    Reconnect driveshaft
    Raise the driveshaft into position and align the U-joint with the pinion flange. Install the U-joint strap bolts and tighten evenly in a cross pattern to ensure even loading. Torque to specification.
    Torque spec

    Driveshaft U-Joint Straps20 Nm (15 lb-ft)
11. 11

    Refill differential with gear oil
    Reinstall the drain plug if removed. Locate the differential fill plug on the side of the housing. Remove the fill plug and add 75W-90 GL-5 gear oil until it reaches the bottom of the fill hole (approximately 2.0 quarts). Allow a moment for oil to settle, then verify level is at the fill hole. Reinstall fill plug securely.

Reassembly

1. Ensure all fasteners are tightened to proper specifications
2. Verify no tools or rags were left in the work area
3. Lower vehicle from jack stands safely
4. Dispose of used gear oil according to local regulations

Verification

• Check for leaks around the pinion seal with vehicle running and transmission in gear (wheels off ground) for 2-3 minutes
• Test drive vehicle and verify no abnormal noise from differential
• After test drive, inspect pinion seal area again for any signs of leakage
• Recheck differential fluid level after 50-100 miles of driving
• Monitor for leaks during first 500 miles; some minor seepage may occur as seal seats but should stop

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