Differential Rebuild - Front

Complete disassembly, inspection, and rebuild of the front power transfer unit differential on a 2017 Maserati Levante 3.0L V6 Twin Turbo RWD, including bearing and seal replacement.

Warnings

Tools required

Parts

• Front differential rebuild kit (bearings, seals, shims) × 1 — Use OEM specification
• Front differential cover gasket or RTV sealant × 1 — Use OEM specification
• Drain plug copper washer × 1 — Use OEM specification
• Fill plug copper washer × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Axle seals × 2 — Use OEM specification
• Crush sleeve (if applicable) × 1 — Use OEM specification
• Gear marking compound × 1 — Use OEM specification

Fluids

• 75W-140 Synthetic Gear Oil (front differential service) — 2.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery terminal and isolate cable
3. Raise front of vehicle and support on jack stands at manufacturer-specified lift points
4. Remove both front wheels using star pattern loosening sequence
5. Allow differential to cool to ambient temperature if vehicle was recently driven
6. Place drain pan under front differential assembly
7. Mark driveshaft and differential flange orientation with paint pen for reinstallation alignment
8. Take comprehensive photographs of assembly before disassembly

Procedure

1. 1

   Drain differential fluid
   Locate drain plug on bottom of front differential housing. Clean area around drain plug. Remove drain plug and allow all gear oil to drain into pan. Inspect drained fluid for metal particles or debris indicating internal damage. Remove and discard copper crush washer from drain plug.
   Torque spec

   Drain Plug43 Nm (32 lb-ft)
2. 2

   Disconnect driveshaft from front differential
   Remove four bolts securing front driveshaft to differential input flange. Support driveshaft with wire or strap to prevent damage to center support bearing. Ensure alignment marks made during preparation are visible for reassembly.
   ⚠Do not allow driveshaft to hang unsupported as this will damage the center support bearing.
   Torque spec

   Driveshaft Bolts79 Nm (58 lb-ft)
3. 3

   Remove CV axles from differential
   Remove CV joint bolts connecting both inner CV joints to differential output flanges. Support CV axles and carefully separate from differential. Cap or plug output flange openings to prevent contamination during rebuild.
   Torque spec

   CV Joint Bolts64 Nm (47 lb-ft)
4. 4

   Remove differential cover
   Remove all differential cover bolts in criss-cross pattern to prevent warping. Carefully pry cover away from housing using soft pry tool. Clean all RTV sealant from cover and housing mating surfaces using plastic scraper and solvent. Inspect cover for cracks or damage.
   ℹ️Take note of any shims behind cover for reference during reassembly.
   Torque spec

   Cover Bolts36 Nm (26 lb-ft)
5. 5

   Mark and measure gear backlash and bearing preload
   Mount dial indicator to housing with probe contacting ring gear tooth at 90 degrees to tooth face. Rock pinion gear back and forth and record backlash measurement. Measure and record pinion bearing preload using inch-pound torque wrench on pinion nut. Take multiple measurements and document all readings. Mark gear tooth contact pattern using gear marking compound on 4-5 teeth, then rotate through one full revolution.
   ℹ️These measurements are critical for proper reassembly. Document thoroughly with photos and written notes.
6. 6

   Disassemble differential carrier assembly
   Install differential spreader tool on housing and carefully spread case only enough to remove carrier assembly (maximum 0.020 inches). Remove carrier bearing caps after marking orientation. Carefully lift carrier assembly from housing. Remove ring gear bolts and separate ring gear from carrier. Disassemble carrier by driving out pinion shaft roll pin and removing pinion shaft, side gears, and spider gears. Inspect all gears for wear, scoring, or damage.
   ⚠️Do not over-spread differential housing. Exceeding 0.020 inches can permanently damage the housing casting.
7. 7

   Remove pinion gear assembly
   Hold pinion flange with holder tool and remove pinion nut. Use appropriate puller to remove pinion flange from shaft. Carefully tap pinion shaft out of housing from front using soft hammer. Catch pinion as it exits housing to prevent dropping. Remove pinion bearing races, shims, and crush sleeve (if equipped). Label and store all shims in organized manner.
   ⚠Pinion nut is high torque. Ensure pinion flange is properly secured before loosening nut.
8. 8

   Remove all bearings and seals
   Use bearing puller to remove carrier bearings from carrier assembly. Press out pinion bearings from pinion shaft. Remove pinion seal from housing using seal puller. Remove axle seals from output flanges. Remove all bearing races from housing and carrier using brass drift and hammer. Clean all components thoroughly with solvent and compressed air. Inspect all bearing surfaces, gear teeth, and housing bores for damage.
   ℹ️Inspect ring gear and pinion for wear patterns indicating improper mesh. If gears show significant wear, complete gear set replacement is recommended.
9. 9

   Install new bearing races and prepare housing
   Using bearing race installer or press, install new carrier bearing races into housing bores ensuring they are fully seated. Install new pinion bearing races into housing ensuring proper depth and alignment. Clean all bearing surfaces with lint-free towels. Apply thin coat of assembly lube to all bearing races.
   ⚠Bearing races must be driven in squarely to prevent cocking or damage. Use proper size driver that contacts race outer edge only.
10. 10

    Assemble and shim pinion gear
    Press new bearings onto pinion shaft using bearing installer and press. Install original shim pack as starting point (adjust based on new bearing measurements if provided by manufacturer). Apply assembly lube to bearings. Install new crush sleeve on pinion shaft. Insert pinion assembly into housing with careful alignment. Install pinion flange and new pinion nut. Tighten pinion nut gradually while checking bearing preload with inch-pound torque wrench. Target preload: 15-25 inch-pounds for new bearings. DO NOT back off nut to reduce preload - must start over with new crush sleeve if exceeded.
    ⚠️Pinion bearing preload is critical. If target preload is exceeded, you must replace crush sleeve and start over. Never loosen pinion nut to reduce preload.
    ℹ️Tighten pinion nut in small increments (1/8 turn) and check preload frequently as you approach target specification.
11. 11

    Assemble differential carrier
    Press new carrier bearings onto carrier hub. Reassemble internal components: install side gears with thrust washers, install spider gears with pinion shaft, align roll pin hole and install new roll pin, stake roll pin ends. Mount ring gear to carrier using thread locker on bolts and tighten to specification in star pattern. Verify ring gear runout with dial indicator (maximum 0.003 inches).
    ℹ️Ensure thrust washers are properly positioned and lubricated before assembling spider gears.
12. 12

    Install carrier assembly and set backlash
    Apply assembly lube to carrier bearings. Use differential spreader to spread housing (maximum 0.020 inches). Install carrier assembly with bearing races into housing. Remove spreader. Install bearing caps in originally marked orientation. Install and tighten bearing cap bolts to specification. Mount dial indicator and measure backlash at ring gear. Adjust backlash to specification (typically 0.005-0.008 inches) by moving shims from one side to other. Equal thickness shims must be maintained on both sides. Recheck pinion depth and tooth contact pattern using gear marking compound.
    ℹ️Proper gear contact pattern should show contact in center of tooth face. Adjust pinion depth shims if pattern is incorrect.
13. 13

    Install new seals
    Using appropriate seal driver, install new pinion seal into housing ensuring it seats flush and square. Install new axle seals into output flange bores, driving until fully seated. Apply thin coat of gear oil to seal lips before installation.
14. 14

    Reinstall differential cover
    Apply continuous 3mm bead of RTV sealant to cover mating surface or install new cover gasket per manufacturer specification. Install cover onto housing and install all bolts finger-tight. Tighten cover bolts in criss-cross pattern to specification. Allow RTV to cure per manufacturer directions before filling (typically 1 hour minimum).
    ℹ️Do not overtighten cover bolts as this can distort cover and cause leaks.
    Torque spec

    Cover Bolts36 Nm (26 lb-ft)
15. 15

    Fill differential and reconnect components
    Install drain plug with new copper washer and torque to specification. Remove fill plug and fill differential with 75W-140 synthetic gear oil until level reaches bottom of fill plug hole (approximately 2.0-2.5 quarts). Install fill plug with new copper washer and torque to specification. Reconnect CV axles to differential output flanges ensuring proper alignment and torque CV joint bolts to specification. Reconnect front driveshaft to input flange aligning marks made during disassembly and torque bolts to specification. Install front wheels and torque lug nuts to specification in star pattern.
    Torque spec

    Drain Plug43 Nm (32 lb-ft)

    Fill Plug43 Nm (32 lb-ft)

    CV Joint Bolts64 Nm (47 lb-ft)

    Driveshaft Bolts79 Nm (58 lb-ft)

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to specification using calibrated torque wrench
2. Double-check that alignment marks on driveshaft match original orientation
3. Verify no tools or parts are left in wheel wells or under vehicle
4. Reconnect negative battery terminal

Verification

• Lower vehicle and test drive at low speeds (under 20 mph) for first 5 miles to seat bearings
• Listen for abnormal whine, growl, or clunking noises from front differential during acceleration and deceleration
• Check for fluid leaks around cover, pinion seal, and axle seals after test drive
• Recheck differential fluid level after test drive and top off if necessary
• Perform final test drive at highway speeds and verify smooth operation with no noise or vibration
• Schedule follow-up inspection after 500 miles to recheck fluid level and verify no leaks have developed

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