Torque Converter

Complete removal and replacement of the torque converter on a 2009 Aston Martin DB9 with 6.0L V12, requiring transmission removal, flexplate access, and converter replacement.

Warnings

Tools required

Parts

• Torque converter × 1 — Use OEM specification for ZF 6HP26 transmission
• Transmission pan gasket × 1 — Use OEM specification
• Transmission filter × 1 — Use OEM specification
• Flexplate bolts × 1 — Use OEM specification, replace if thread-locking compound present
• Propeller shaft center bearing bolts × 1 — Use OEM specification with thread-locking compound
• Transmission mount fasteners × 1 — Use OEM specification
• Exhaust gaskets × 1 — Replace if disturbed during removal

Fluids

• Touchtronic 6-speed ZF ATF — 9.5 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Disconnect negative battery terminal and secure cable away from battery
3. Raise vehicle on lift to working height or use jack stands at all four corners
4. Remove engine undertray panels using Torx fasteners
5. Place drain pan under transmission and drain transmission fluid via drain plug
6. Mark propeller shaft alignment to differential flange and transmission flange for reassembly reference
7. Mark all electrical connectors and hose positions with tape or labels for correct reinstallation
8. Install engine support bar across engine bay or attach overhead hoist to engine lift points

Procedure

1. 1

   Remove exhaust system sections
   Disconnect exhaust system from catalytic converters rearward to transmission crossmember area. Remove exhaust hangers and lower exhaust system to provide clearance for transmission removal. The exhaust may be removed in sections or as a complete assembly depending on access. Inspect exhaust gaskets and replace if compressed or damaged. Note: Use OEM specification for ZF 6HP26 transaxle (rear-mounted in transaxle configuration) Note: Use OEM specification for the ZF 6-speed Touchtronic rear transaxle. VERIFY: The DB9 uses a rear-mounted transaxle integrated with the differential, not a front-mounted transmission. Note: Use OEM specification for the ZF 6-speed automatic transmission (verify ZF 6HP26 vs 6HP28 against this vehicle's VIN)
2. 2

   Disconnect propeller shaft
   Remove the center bearing support bracket fasteners from the chassis. Address the torque tube / driveshaft coupling as specified in OEM documentation for this platform; verify exact flange bolt counts and the torque-tube removal procedure before proceeding. VERIFY DRIVELINE: The DB9 uses a torque tube connecting the engine to the rear transaxle (which incorporates the differential). There is no separate propeller-shaft-to-differential flange — confirm the actual driveshaft/torque tube configuration before removing any bolts. Lower the propeller shaft assembly and remove from vehicle. Cap the transmission output to prevent fluid loss. Note: Remove the propeller shaft/torque tube flange fasteners as applicable to this vehicle's driveline layout (verify the DB9 transaxle/torque-tube configuration and exact bolt count against OEM documentation).
3. 3

   Disconnect transmission electrical connections
   Disconnect the transmission range sensor connector, vehicle speed sensor connector, and solenoid body harness connector from the transmission. Remove any harness brackets or clips securing wiring to the transmission case. Position wiring harnesses away from transmission removal path.
4. 4

   Disconnect transmission cooler lines and breather
   Position drain pan under transmission cooler line connections. Disconnect the transmission cooler feed and return lines from the transmission case using appropriate line wrenches to avoid damaging fittings. Disconnect the transmission breather hose from the top of the transmission. Cap all open ports to prevent contamination.
5. 5

   Remove transmission crossmember
   Position transmission jack under transmission oil pan with a wooden block or adapter to distribute load. Raise jack slightly to support transmission weight. Remove the transmission mount-to-crossmember fasteners. Remove the crossmember-to-chassis fasteners (typically E-Torx or Torx fasteners on each side). Lower and remove crossmember from vehicle.
6. 6

   Remove starter motor
   Disconnect the starter motor electrical connections (main battery cable and signal wire). Locate the starter motor on this platform (engine/driveplate region, not a conventional rear bellhousing). Disconnect starter electrical connections, remove the starter mounting bolts (verify exact count against OEM documentation), and remove the starter. Verify whether the starter opening provides access to the driveplate-to-torque-converter fasteners on this torque-tube layout before relying on it.
7. 7

   Remove bellhousing-to-engine bolts
   Remove all bellhousing-to-engine block bolts. These fasteners are located around the perimeter of the bellhousing and may be a combination of Torx and E-Torx types. Verify the exact bellhousing/torque-tube housing bolt count and locations against OEM documentation before removal (do not assume a conventional 8-12 bolt count). Note the location of each bolt length for correct reinstallation. Some upper bolts may require access from the engine bay.
8. 8

   Access torque converter bolts
   Through the starter motor opening or dedicated access hole in the bellhousing, rotate the engine crankshaft using a socket on the crankshaft pulley bolt to bring each torque converter bolt into view. The torque converter attaches to the flexplate with a set of bolts/nuts spaced evenly around the flexplate — VERIFY exact count (commonly 4 or 6 on ZF applications) against OEM documentation. Mark the position of one bolt hole on the flexplate and converter for installation reference. Note: Verify the exact torque converter-to-flexplate bolt count and spacing against OEM documentation for the ZF 6HP26 in this vehicle before proceeding. Note: The torque converter is attached to the driveplate with evenly spaced bolts/nuts — verify the exact count against OEM documentation for the DB9 ZF 6HP application before proceeding. Mark the position of one bolt hole on the driveplate and converter for installation reference.
9. 9

   Remove torque converter-to-flexplate bolts
   Using a flywheel holding tool or ring gear lock to prevent crankshaft rotation, remove all torque converter-to-flexplate bolts (verify exact count per OEM specification) through the access opening. Rotate the crankshaft as needed to access each bolt. These bolts may have thread-locking compound. Once removed, push the torque converter rearward toward the transmission to disengage it from the flexplate. Note: Using a flywheel holding tool or ring gear lock to prevent crankshaft rotation, remove all torque converter-to-flexplate bolts through the access opening (VERIFY exact count against OEM documentation). Note: remove all torque converter-to-flexplate bolts through the access opening (verify exact count against OEM documentation)
10. 10

    Separate transmission from engine
    Verify all fasteners, electrical connections, cooler lines, and propeller shaft are disconnected. Ensure transmission jack is securely supporting the transmission weight. Carefully pull transmission rearward away from engine, keeping it level. The transmission must move straight back to clear the dowel pins and avoid damaging the input shaft. Once the input shaft clears the crankshaft, lower the transmission jack and remove transmission from under vehicle.
11. 11

    Remove torque converter from transmission
    With transmission on a secure work surface, carefully pull the torque converter forward off the transmission input shaft. The converter should slide off once it clears the oil pump drive. Tilt the converter slightly to drain residual ATF into a drain pan. Inspect the converter hub for wear, scoring, or discoloration. Inspect the transmission input shaft splines and oil pump drive for damage.
12. 12

    Inspect flexplate and crankshaft
    With transmission removed, inspect the flexplate for cracks, heat discoloration, or damaged bolt holes. Check flexplate runout using a dial indicator if warpage is suspected; compare against the OEM-specified runout limit for this platform. Inspect the crankshaft flange and dowel pins for damage. Clean the flexplate and crankshaft mating surfaces with brake cleaner. If flexplate damage is present, flexplate removal and replacement is required (flexplate-to-crankshaft bolts require specific torque and sequence). Note: Check flexplate runout using a dial indicator if warpage is suspected (compare against OEM runout limit — verify specification before condemning the flexplate). Note: Check flexplate runout using a dial indicator if warpage is suspected (verify the maximum allowable runout specification against OEM documentation).
13. 13

    Install new torque converter
    Apply a small amount of clean ATF to the torque converter hub and splines. Align the converter hub with the transmission oil pump drive and carefully slide the converter onto the input shaft. Rotate the converter while pushing it forward to engage the splines. The converter must fully seat onto the oil pump drive and input shaft splines, typically felt as it drops in with distinct engagement steps - verify full engagement against OEM procedure before mating transmission to engine. Measure the distance from the bellhousing/converter housing mating surface to the torque converter mounting lugs to confirm proper seating. Verify the correct seating-depth specification against OEM documentation for the ZF 6HP transaxle before proceeding — do not rely on any assumed numeric value. If a dial indicator was used during removal to measure engagement depth, match this measurement. Note: Measure the distance from the bellhousing mating surface to the torque converter mounting lugs to confirm proper seating (VERIFY the correct seating-depth specification from OEM documentation before proceeding). Note: Measure the distance from the bellhousing mating surface to the torque converter mounting lugs to confirm proper seating (verify the correct seating depth specification against OEM documentation).
14. 14

    Install transmission to engine
    Apply a thin film of high-temperature grease to the transmission input shaft splines (do not over-lubricate). Position transmission on transmission jack and raise into position. Reinstall the transaxle to the rear subframe/mount and reconnect it to the engine via the torque tube and driveshaft per OEM procedure. Keep the torque converter pushed fully into the transaxle during installation. Verify correct alignment of the torque-tube/driveshaft coupling and that the converter remains fully seated before torquing fasteners; do not assume a direct transmission-to-engine-block dowel-pin mating. If resistance is met, do not force - lower transmission slightly, verify alignment, and retry. Install 2-3 bellhousing bolts finger-tight to hold position before installing remaining bolts.
15. 15

    Install bellhousing bolts
    Install all bellhousing-to-engine block bolts in their correct locations (noting different lengths recorded during removal). Tighten bolts in a cross-pattern to pull the bellhousing evenly to the engine block. Torque all bellhousing bolts to manufacturer specification (VERIFY exact OEM torque values — do not use an assumed value). Note: Torque all bellhousing bolts to manufacturer specification - verify the exact OEM torque value for this platform before tightening. Note: Torque all bellhousing bolts to manufacturer specification (verify exact torque value against OEM documentation before tightening). Note: verify the exact OEM torque specification before tightening; do not use an assumed numeric value
16. 16

    Install torque converter to flexplate
    Rotate the crankshaft to align the flexplate bolt holes with the torque converter lugs. Align the reference marks made during removal. Install all torque converter-to-flexplate bolts finger-tight (verify exact count against OEM documentation). Using a flywheel holding tool to prevent rotation, tighten the bolts evenly in a star pattern (alternating between bolts).
    Torque spec

    Torque Converter Bolts45 Nm (33 lb-ft)
17. 17

    Install starter motor
    Position starter motor into bellhousing and install mounting bolts. Torque starter bolts to OEM specification. Reconnect starter motor electrical connections (main battery cable and signal wire). Verify all connections are secure and wiring is routed away from exhaust and moving components.
18. 18

    Install transmission crossmember and mount
    Raise transmission slightly with transmission jack to align with crossmember mounting points. Position crossmember and install crossmember-to-chassis fasteners finger-tight. Install transmission mount-to-crossmember fasteners finger-tight. Verify transmission alignment, then torque all crossmember and mount fasteners to OEM specification. Remove transmission jack.
19. 19

    Reconnect transmission cooler lines and breather
    Remove caps from transmission cooler line ports. Connect transmission cooler feed and return lines to transmission, ensuring correct routing. Tighten fittings to OEM specification using line wrenches. Connect transmission breather hose to top of transmission. Verify all connections are secure and lines are routed away from exhaust and moving components.
20. 20

    Reconnect transmission electrical connections
    Reconnect transmission range sensor connector, vehicle speed sensor connector, and solenoid body harness connector to transmission. Install all harness brackets and clips. Verify each connector is fully seated and locked. Route wiring harnesses as marked during removal.
21. 21

    Install propeller shaft
    Remove cap from transmission output flange. Raise propeller shaft into position and align with reference marks made during removal. Install center bearing support bracket fasteners and torque to OEM specification. Reconnect the torque-tube driveshaft coupling per OEM procedure and torque evenly to OEM specification. Note: the DB9 uses a torque tube to a rear transaxle that incorporates the differential — there is no separate propeller-shaft-to-differential flange. Verify exact bolt count and torque against OEM documentation. Verify propeller shaft rotates freely without binding.
22. 22

    Install exhaust system
    Raise exhaust system into position and install exhaust hangers. Connect exhaust to catalytic converters using new gaskets if originals were damaged. Install and torque all exhaust fasteners to OEM specification. Verify exhaust has adequate clearance from propeller shaft, transmission, and chassis components throughout its range of motion.
23. 23

    Fill transmission with ATF
    Using a fluid transfer pump, add OEM-specified ZF Lifeguard 6 ATF (or OEM-approved equivalent) through the side fill/level plug (this unit is filled from the bottom level plug, not a dipstick/top fill port). Verify the exact fill capacity against OEM documentation. Verify the exact initial fill quantity against OEM specification. This is the initial fill amount. Start engine and allow to idle in Park. Check fluid level via the side fill/level plug with transmission fluid temperature in the ZF-specified range (typically 30-50°C) - do not check at full operating temperature. Add additional fluid as needed to bring level to proper range. Cycle transmission through all gear ranges while stationary, then recheck fluid level. Note: Using a fluid transfer pump, add the OEM-specified ZF Lifeguard 6 ATF via the fill/level plug (VERIFY correct fluid specification and fill capacity from OEM documentation — this unit is typically filled from the bottom level plug, not a dipstick tube). Note: Using a fluid transfer pump, fill the transmission with the OEM-specified ZF 6HP ATF (Shell/ZF Lifeguard-type) through the side fill/level plug, then perform a level check at the ZF-specified fluid temperature. Verify exact fill quantity and fluid spec against OEM documentation.
24. 24

    Install undertray panels and final checks
    Install engine undertray panels using Torx fasteners. Lower vehicle to ground. Reconnect negative battery terminal. Clear any diagnostic trouble codes that may have set during battery disconnect. Start engine and verify no transmission fluid leaks at cooler lines, pan gasket, or torque converter area. Perform a test drive to verify proper transmission operation, smooth shifts, and torque converter lockup function.

Reassembly

1. Torque all fasteners to manufacturer specifications using a calibrated torque wrench
2. Ensure torque converter is fully seated on transmission input shaft before mating transmission to engine - verify engagement depth measurement
3. Align propeller shaft with reference marks to maintain driveline balance
4. Use new gaskets for exhaust connections if originals are compressed or damaged
5. Verify transmission fluid level with engine at operating temperature and adjust as needed
6. Route all wiring harnesses and hoses as originally positioned to avoid contact with exhaust or moving components

Verification

• Start engine and verify no transmission fluid leaks at all connection points, particularly cooler lines and pan gasket
• With engine at idle in Park, verify transmission engages all forward and reverse gears smoothly
• Perform a test drive and verify smooth acceleration with no shudder, vibration, or unusual noises from torque converter area
• Verify torque converter lockup engages properly at cruising speed (typically 4th-6th gears above 45 mph)
• Check transmission fluid level with engine at operating temperature and top off if needed
• Scan for diagnostic trouble codes related to transmission operation and clear if no current faults exist
• Verify no exhaust leaks and adequate clearance between exhaust and propeller shaft
• Re-torque flexplate bolts and torque converter bolts after initial test drive as a precautionary measure

Related trouble codes on this vehicle

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