Limited Slip Clutch Pack

Remove rear differential assembly, disassemble limited slip differential unit, replace clutch pack and internal components, reassemble differential and reinstall with new fluid.

Warnings

Tools required

Parts

• Limited slip clutch pack kit × 1 — Use OEM specification for DB9 rear differential
• Differential cover gasket × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Axle seals × 2 — Use OEM specification
• Crush washer for differential drain plug × 1 — Use OEM specification
• Crush washer for differential fill plug × 1 — Use OEM specification
• Differential shim set × 1 — Use OEM specification for backlash adjustment
• Bearing preload shim set × 1 — Use OEM specification
• Driveshaft flange bolts × 4 — Use OEM specification (typically replaced)

Fluids

• 75W-140 synthetic gear oil — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery terminal to prevent inadvertent activation of stability control systems
3. Raise vehicle on lift or support securely on four jack stands at manufacturer-specified lift points
4. Remove rear wheels and set aside
5. Place drain pan under differential and allow adequate cooling time if vehicle was recently operated
6. Take photographs of driveshaft orientation and axle positions for reference during reassembly

Procedure

1. 1

   Drain differential fluid
   Locate drain plug on bottom of differential housing. Clean area around drain plug thoroughly. Using appropriate socket, remove drain plug and allow all gear oil to drain into pan. Inspect drained fluid for metal particles or debris indicating wear. Remove fill plug on side of differential housing to allow complete drainage and to verify fluid condition.
2. 2

   Remove rear exhaust section
   The rear exhaust system may require lowering for transaxle access clearance. Support exhaust with jack stands or hanging straps. Remove exhaust hanger fasteners and clamp connections per the DB9 service manual. Lower exhaust assembly sufficiently to provide clearance. Disconnect any oxygen sensors in the work area and secure wiring away from the transaxle. Confirm all steps against factory transaxle service data.
3. 3

   Disconnect driveshaft from differential
   Mark alignment position of driveshaft flange to differential pinion flange with paint or scribe. Remove the flange bolts connecting driveshaft to differential (bolt count per factory service manual). Support driveshaft weight and lower it carefully. Secure driveshaft to underbody with wire or strap to prevent damage to center support bearing. Install a plug or tape over differential companion flange to prevent fluid leakage and contamination. Note: Verify the DB9 final-drive/transaxle mounting configuration against the factory service manual before proceeding, as the DB9 integrates the differential within the rear transaxle assembly.
   ⚠Driveshaft is heavy and awkward. Support weight before removing final bolt to prevent sudden drop.
4. 4

   Disconnect rear axle shafts
   At each rear wheel hub, remove the axle nut using breaker bar and appropriate socket. Remove the CV joint-to-differential flange bolts per factory service manual (bolt count to be verified from FSM). Support axle shaft weight and pull axle assembly outward from differential, allowing CV joint to separate from flange. Secure axle shafts to suspension components to keep them out of work area. Cap or cover differential side outputs to prevent contamination. Note: At each rear wheel hub, disconnect the driveshaft per DB9 service procedures. Remove the driveshaft-to-differential flange fasteners (verify exact count against factory service manual). Support driveshaft weight and separate from differential output. Secure driveshaft to suspension components to keep them out of work area. Note: At each rear wheel hub, remove the axle nut using breaker bar and appropriate socket. Detach the rear halfshafts from the transaxle output flanges per the DB9 transaxle service procedure. Support axle shaft weight and separate the halfshaft from the output flange. Verify exact fastener type and count against factory service data before proceeding.
   Torque spec

   CV Bolts60 Nm (44 lb-ft)

   Axle Nut250 Nm (184 lb-ft)
5. 5

   Disconnect differential mounts and support brackets
   Position transmission jack or suitable support under differential housing center. The DB9 differential is mounted with a combination of front mounting bolts, rear mounting bolts, and lateral support brackets. Remove fasteners securing differential nose to subframe (bolt count per factory service manual). Remove rear differential mount fasteners. Remove lateral support bracket fasteners on both sides of differential housing. Ensure differential weight is fully supported on jack before removing final mounting fasteners. Note: The DB9 rear transaxle is mounted to the rear subframe and connected via the torque tube. Remove transaxle mounting fasteners per the factory service procedure. Confirm exact mounting points and fastener counts against the DB9 service manual before removal. Note: The DB9 rear transaxle assembly is heavy (full gearbox plus final drive — significantly heavier than a bare differential). Verify the assembly weight in the factory service manual and ensure the jack is rated accordingly.
   ⚠️Differential assembly weighs approximately 45-60 kg. Ensure jack is rated for weight and positioned securely at differential center of gravity.
6. 6

   Remove differential assembly from vehicle
   With all mounting fasteners removed and differential fully supported on jack, carefully lower differential assembly. Maneuver assembly rearward and downward to clear subframe and suspension components. An assistant is helpful to guide assembly during removal. Once clear of vehicle, transport differential to clean workbench for disassembly.
7. 7

   Remove differential cover and inspect
   Place the transaxle assembly on a workbench. Disassemble the transaxle case per factory service procedure to access the final drive / limited slip unit. Inspect gear oil residue and internal components for metal particles, scoring, or unusual wear patterns. Photograph ring gear and pinion mesh pattern for reference. Replace all case seals per OEM specification. Note: Open rear transaxle case to access final drive / LSD
8. 8

   Mark and measure gear backlash
   Before disassembly, measure and record gear backlash using dial indicator mounted to housing with indicator tip on ring gear tooth. Rock pinion gear while monitoring indicator. Record backlash at 4 points around ring gear (90-degree intervals). Mark bearing caps with punch marks or paint indicating their orientation and mating surfaces - caps are machined as matched sets and must return to original positions. Note position and thickness of any shims behind bearing caps for reference. Note: Factory backlash specification must be obtained from the Aston Martin service manual for this differential (value not verified in database). Record all measurements for comparison during reassembly. Note: Backlash specification must be verified against the DB9 factory service manual. Record all measurements for comparison during reassembly. Note: Record all measurements for comparison during reassembly. Obtain the exact factory backlash specification from the DB9 service manual before judging acceptability. Note: Factory backlash specification must be obtained from the Aston Martin DB9 factory service manual for this final drive (value not verified). Record all measurements for comparison during reassembly.
   ℹ️Factory backlash specification is typically 0.13-0.18mm for this differential type. Record all measurements for comparison during reassembly.
9. 9

   Remove differential carrier assembly
   Remove bearing cap bolts from both carrier bearing caps. Bearing cap bolt count per factory service manual (count not verified — confirm against the DB9 FSM, noting the final drive is integral to the rear transaxle). Carefully pry bearing caps off using appropriate tools. Note the position and thickness of any shims behind the caps - keep shims organized by side. Remove carrier assembly (ring gear, spider gears, and side gears) from housing. The carrier may require light tapping with dead blow hammer to break it free from bearing races. Set carrier assembly on clean work surface.
10. 10

    Disassemble ring gear from carrier
    The ring gear is bolted to the differential carrier with the number of bolts specified in the factory service manual. Mark ring gear orientation to carrier with paint for reassembly reference. Remove all ring gear bolts working in star pattern. Use brass drift or soft mallet to tap ring gear off carrier if tight. Inspect ring gear teeth and mounting flange for wear or damage.
11. 11

    Remove differential pin and spider gears
    Locate the differential cross pin (spider gear shaft) which is retained by a roll pin or threaded lock bolt. Remove the retaining pin or bolt. Drive differential pin out of carrier using brass punch. Remove spider gears (pinion gears) and side gears from carrier, keeping track of any thrust washers behind each gear. Inspect all gears and thrust washers for wear, scoring, or discoloration.
12. 12

    Remove limited slip clutch pack
    With spider gears removed, access to the limited slip clutch packs is now available. The DB9 uses a multi-plate clutch design with alternating friction plates and steel plates on each side gear. Carefully remove clutch packs, keeping left and right sides separate and organized. Note the order and orientation of friction plates, steel plates, and any backing plates or pressure rings. Count plates and measure stack height with calipers for reference. Inspect all plates for glazing, scoring, or uneven wear.
    ℹ️Clutch pack configuration (plate count and thickness) determines limited slip preload. Record exact configuration for proper reassembly.
13. 13

    Clean all components thoroughly
    Clean carrier housing, gears, and all reusable components with solvent and allow to air dry. Remove all old gear oil, debris, and friction material residue. Inspect carrier bearing races in housing for pitting or damage. Inspect side gear splines and spider gear surfaces for excessive wear. Clean differential housing interior thoroughly, removing any metal particles or debris from bottom of case.
14. 14

    Install new limited slip clutch pack
    Begin assembly with new clutch pack components from kit. Install clutch plates in correct order per kit instructions, typically alternating friction plates and steel plates. Some kits include pre-soaking instructions for friction plates in gear oil - follow manufacturer specifications. Install clutch packs on both side gears ensuring correct plate count and orientation. Measure total stack height and compare to specifications or original measurements. If adjustable, set clutch pack preload per kit instructions using correct backing plate or wave spring configuration.
15. 15

    Reassemble side gears and spider gears
    Install side gears with new clutch packs into carrier housing. Install spider gears with thrust washers in carrier, meshing with both side gears. Rotate spider gears to align pin holes. Install differential cross pin through carrier and spider gears. Install new roll pin or lock bolt to retain cross pin per original configuration. Apply thread locker to lock bolt if equipped. Verify spider gears and side gears rotate with appropriate resistance indicating proper clutch pack engagement.
16. 16

    Install ring gear to carrier
    Position ring gear on carrier in original orientation per alignment marks. Install all ring gear bolts hand tight. Apply medium-strength thread locker to bolt threads. Torque ring gear bolts in star pattern per OEM service data (verify exact torque value and tightening method in the factory service manual; ring gear bolts are right-hand thread unless the FSM explicitly specifies otherwise). Verify ring gear is seated flush to carrier mounting surface with no gaps. Note: consult factory service manual for the exact ring gear bolt torque specification and tightening method (value not provided in database). Note: per factory service manual specification — do not estimate Note: Ring gear bolt torque specification not provided in database - consult the Aston Martin factory service manual for the exact value and tightening method. Do not estimate.
    ℹ️Ring gear bolt torque specification not provided in database - consult factory service manual for exact value, typically 80-110 Nm for this application.
17. 17

    Install carrier bearings and shims
    If carrier bearings were removed, press new bearings onto carrier using bearing driver or press. Install carrier bearing shims in original positions and thicknesses (unless backlash adjustment is required). Place carrier assembly with bearings and shims into differential housing. Install bearing caps in original positions per alignment marks. Install bearing cap bolts and torque in cross pattern. Initial installation should use original shim configuration.
18. 18

    Measure and adjust gear backlash
    With carrier installed, measure gear backlash using dial indicator at multiple points around ring gear. Compare measurements to original readings and the DB9 factory backlash specification (verify in service manual). If backlash is outside specification, adjust by moving shims from one side of carrier to the other - removing shims from right side and adding to left side decreases backlash, and vice versa. Shim changes must be equal to maintain bearing preload. Re-measure after each adjustment until backlash is within specification at all measurement points. Note: Compare measurements to original readings and the factory backlash specification obtained from the Aston Martin service manual.
    ⚠Bearing cap bolts must be torqued to specification before measuring backlash. Loose caps will give false readings.
19. 19

    Check gear tooth contact pattern
    Apply gear marking compound to several ring gear teeth. Rotate pinion gear through several revolutions in both directions while applying light load. Examine contact pattern on ring gear teeth - pattern should be centered on tooth face for drive and coast sides. If pattern is incorrect, backlash or pinion depth adjustment may be required. Consult service manual for pattern interpretation and correction procedures. Clean marking compound from gears before final assembly.
20. 20

    Install differential cover and fill with fluid
    Clean differential cover and housing mating surfaces thoroughly. Apply thin bead of RTV silicone to housing mating surface or install new gasket per manufacturer specification. Install differential cover and cover bolts. Torque cover bolts in cross pattern to specification. Install new crush washers on drain and fill plugs. Install drain plug and torque to specification. Fill the rear transaxle through the fill hole with the Aston Martin-specified transaxle/final-drive lubricant (correct grade and friction-modifier content per factory service data — do NOT substitute a generic 75W-140) until fluid reaches the bottom of the fill hole. Verify exact fill capacity against the DB9 factory service manual. Install fill plug with new crush washer and torque to specification. Wipe all surfaces clean. Note: Fill with the Aston Martin-specified gear lubricant until fluid reaches the bottom of the fill hole (verify exact grade and capacity in the factory service manual). Note: Fill with the Aston Martin specified transaxle/final drive lubricant to the correct level per factory service data. Verify exact grade and fill capacity against the DB9 service manual before filling. Note: Fill through the fill hole with the Aston Martin specified transaxle lubricant
    ℹ️Allow RTV silicone to cure per manufacturer instructions (typically 1 hour) before filling with fluid if used instead of gasket.
    Torque spec

    Differential Cover Bolts35 Nm (26 lb-ft)
21. 21

    Install differential assembly in vehicle
    With differential fully assembled and filled, position assembly on transmission jack. Carefully raise differential into position, maneuvering around suspension and subframe components. An assistant is helpful to guide assembly into position. Align differential with mounting points and install mounting fasteners hand tight. Install front nose mounting bolts, rear mount bolts, and lateral support brackets. Torque all mounting fasteners to specification in sequence per service manual.
22. 22

    Connect axle shafts to differential
    Guide each axle shaft into position and engage CV joint with differential output flange. Install CV joint-to-flange bolts and torque to specification in star pattern. Install axle nut on each side hand tight (final torque will be performed with wheels installed and vehicle on ground). Verify axle shafts are fully seated and CV joints rotate freely.
    Torque spec

    CV Bolts60 Nm (44 lb-ft)
23. 23

    Connect driveshaft to differential
    Remove plug or tape from differential pinion flange. Guide driveshaft into position and align marks on driveshaft flange to differential flange. Install new flange bolts with thread locker applied. Torque bolts in cross pattern to specification. Verify driveshaft rotates freely with no binding or unusual runout.
24. 24

    Reinstall exhaust and final connections
    Raise exhaust section into position and install all mounting brackets and hangers. Reconnect any oxygen sensor connectors that were disconnected. Verify exhaust has adequate clearance from differential and suspension components. Install rear wheels and torque lug nuts in star pattern to specification. Lower vehicle to ground. With vehicle weight on wheels, torque axle nuts (if equipped) to final specification per factory service manual and secure using the OEM retention method specified for this vehicle. Note: With vehicle weight on wheels, torque hub/driveshaft fasteners to final specification and secure per the DB9 factory service manual retention method.
    ⚠Axle nut must be torqued with vehicle on ground and wheel bearing loaded. Do not torque on jack stands.
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)

    Axle Nut250 Nm (184 lb-ft)

Reassembly

1. Reconnect negative battery terminal
2. Start engine and verify no leaks from differential cover or drain/fill plugs
3. Test drive vehicle in safe area, starting with gentle acceleration and turns to verify proper limited slip operation
4. Listen for any unusual gear noise, particularly whining or clunking that would indicate improper backlash or bearing preload
5. After initial test drive (10-15 miles), re-check differential fluid level and top off if necessary
6. Re-check all mounting fasteners for proper torque after test drive
7. Monitor differential operation and fluid condition for first 500 miles, then perform fluid change to remove any break-in debris

Verification

• Verify differential fluid level is correct at fill plug hole with vehicle level
• Confirm no leaks from differential cover, drain plug, fill plug, axle seals, or pinion seal
• Test limited slip operation by performing low-speed turn on dry pavement - inside wheel should chirp slightly indicating clutch pack engagement
• Verify smooth operation through all gears with no whining, howling, or clunking from differential
• Confirm axle nuts are properly torqued and secured with cotter pins or staked
• Check that exhaust system has proper clearance and does not contact differential or suspension
• Verify all mounting fasteners are torqued to specification and differential is secure

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