Replace the differential pinion seal to stop fluid leaks from the front or rear differential where the driveshaft connects.

Warnings

Tools required

Parts

• Differential pinion seal × 1 — Use OEM specification for front or rear differential
• Differential cover gasket or RTV sealant × 1 — Mopar RTV sealant or OEM gasket

Fluids

• Mopar 75W-140 Synthetic Gear Lubricant — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks behind wheels that will remain on ground
3. Raise vehicle and support securely on jack stands at frame rails
4. Allow differential to cool completely if recently driven
5. Identify whether servicing front or rear differential and proceed accordingly

Procedure

1. 1

   Remove driveshaft from differential
   Using paint marker, mark driveshaft orientation to pinion yoke for reinstallation. Remove the four driveshaft flange bolts connecting driveshaft to differential pinion yoke. Support driveshaft and separate from differential. Secure driveshaft out of the way with wire or bungee cord to prevent damage to CV joints.
   Torque spec

   Driveshaft Bolts85 Nm (63 lb-ft)
2. 2

   Drain differential fluid
   Place drain pan under differential cover. Remove differential cover bolts in a crisscross pattern, starting from top bolts and working down. Carefully break cover loose and allow fluid to drain completely into pan. Remove cover and gasket material. Inspect drained fluid for metal shavings or debris that may indicate bearing wear.
   ⚠Gear oil has strong odor and is slippery. Avoid skin contact and ensure adequate ventilation.
   Torque spec

   Differential Cover Bolts39 Nm (29 lb-ft)
3. 3

   Mark pinion position
   Using paint marker, mark exact rotational position of pinion nut on pinion shaft threads. Make corresponding alignment mark on pinion yoke and pinion shaft. These marks are critical for maintaining proper bearing preload during reassembly. Photograph marks if possible for reference.
   ⚠Bearing preload cannot be properly restored if pinion nut is removed completely or tightened beyond original position. Marking is essential.
4. 4

   Remove pinion nut and yoke
   Using pinion holding tool or pipe wrench on yoke to prevent rotation, carefully loosen and remove pinion nut. Count exact number of threads visible above nut before removal. Remove pinion yoke by pulling straight off pinion shaft. If yoke is tight, use a two-jaw puller. Do not strike yoke with hammer as this can damage pinion bearings.
   ⚠Do not allow pinion shaft to rotate during nut removal as this may alter bearing preload.
5. 5

   Remove old pinion seal
   Using seal puller or carefully positioned pry bar, remove old pinion seal from differential housing. Work carefully to avoid damaging seal bore surface in housing. Clean seal bore thoroughly with shop towels, removing all old seal material and debris. Inspect seal bore for scratches, burrs, or damage that could cause new seal to leak.
6. 6

   Install new pinion seal
   Lightly coat outer edge of new seal with gear oil. Verify seal orientation (spring side faces inward toward differential). Using pinion seal installation tool or appropriately sized large socket, drive seal squarely into bore until fully seated and flush with housing. Apply thin coat of gear oil to seal lip before installing yoke.
   ⚠Seal must be installed straight to avoid cocking and leakage. Use proper installation tool to distribute force evenly.
7. 7

   Reinstall pinion yoke
   Align marks on pinion yoke and shaft. Slide yoke onto pinion shaft, ensuring it seats completely. Install pinion nut and hand-tighten. Using holding tool on yoke, tighten pinion nut slowly until it reaches the previously marked position. Nut should stop at exact same thread count and alignment mark made during disassembly.
   ⚠Stop immediately when nut reaches original marked position. Do not overtighten. If nut is tightened beyond mark, entire pinion bearing assembly must be replaced.
8. 8

   Verify pinion preload
   Check that pinion nut is at original position using alignment marks. Rotate pinion by hand to verify smooth operation with appropriate drag from bearing preload. Pinion should turn smoothly without binding or excessive play. If preload feels incorrect, consult OEM bearing preload specifications for rebuild procedure.
9. 9

   Clean and prepare differential cover
   Thoroughly clean differential cover and housing mating surfaces using scraper and shop towels. Remove all old gasket material and RTV sealant. Surfaces must be completely clean and dry for proper seal. If using RTV sealant, apply continuous 3mm bead around cover bolt holes, circling inboard of holes. If using gasket, position on cover.
10. 10

    Install differential cover and fill
    Install differential cover to housing, aligning bolt holes. Install cover bolts and tighten in crisscross pattern to specified torque. Allow RTV to cure for 10 minutes before filling if applicable. Fill differential through fill hole with specified Mopar 75W-140 Synthetic Gear Lubricant until fluid reaches bottom of fill hole (2.0 qt for rear, 1.5 qt for front). Install fill plug.
    Torque spec

    Differential Cover Bolts39 Nm (29 lb-ft)
11. 11

    Reinstall driveshaft
    Align driveshaft to pinion yoke using marks made during removal. Install four driveshaft bolts and tighten in star pattern to specified torque. Verify driveshaft has proper clearance and rotates freely without binding.
    Torque spec

    Driveshaft Bolts85 Nm (63 lb-ft)

Reassembly

1. Double-check all fasteners are tightened to proper torque specifications
2. Verify no tools or materials are left under vehicle
3. Lower vehicle from jack stands carefully
4. If RTV sealant was used, allow to cure per manufacturer instructions before test drive

Verification

• Start engine and shift through all gears to circulate differential fluid
• Check for leaks around pinion seal and differential cover while engine runs
• Test drive vehicle 10-15 miles, making several turns in both directions
• Recheck differential fluid level after test drive and top off if needed
• Inspect pinion seal area and cover gasket for any signs of leakage after 50-100 miles of driving

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