U-Joint

Replace the driveshaft universal joint (U-joint) on a 2009 Aston Martin DB9, including driveshaft removal, U-joint replacement or driveshaft assembly replacement, and reinstallation with proper alignment.

Warnings

Tools required

Parts

• Driveshaft universal joint (U-joint) × 1 — Use OEM specification or Spicer/GKN equivalent
• U-joint strap bolts (if reuse not recommended) × 4 — Use OEM specification
• Differential flange gasket or sealant (if equipped) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake.
2. Raise vehicle on lift or securely support on jack stands at all four corners, providing adequate clearance to access underside.
3. Remove rear wheels to improve access and reduce vehicle weight on supports.
4. Inspect driveshaft, U-joints, center support bearing, and CV joints for obvious damage, excessive play, or signs of previous repair.
5. Clean driveshaft, differential flange, and transmission output flange areas to remove dirt and debris for clear marking.

Procedure

1. 1

   Mark driveshaft phasing and alignment
   Using a center punch or paint marker, create alignment marks across the driveshaft-to-transaxle flange joint and the driveshaft-to-engine coupling joint. Mark both the shafts and flanges in at least two locations 180 degrees apart to ensure exact rotational alignment during reinstallation. Photograph the markings for reference.
2. 2

   Support driveshaft with transmission jack
   Position a transmission jack or adjustable support stand under the rigid torque tube assembly to support its weight during removal, per the Aston Martin workshop manual. Note that the torque tube is a structural member connecting the front engine to the rear transaxle; follow the manual's sequence for detaching it. Secure the assembly to the jack with a strap or chain to prevent it from falling. Adjust height to take slight pressure off the mounting points without lifting the vehicle. Secure the driveshaft to the jack with a strap or chain to prevent it from falling. Note: Support the torque tube/driveshaft assembly at its mounting points with a transmission jack or adjustable support stand to take its weight during removal.
3. 3

   Remove rear driveshaft U-joint flange connection
   At the rear transaxle, locate the fasteners securing the driveshaft coupling to the transaxle input flange. Consult the Aston Martin workshop manual for the exact coupling type, fastener count, and bolt drive size before removal. Support the driveshaft end as you remove the final bolts to prevent it from dropping. Carefully separate the U-joint from the differential flange, taking care not to damage bearing caps or allow them to fall off. Note: Locate the fasteners securing the driveshaft coupling to the differential/transaxle flange. Remove the fasteners using the appropriate socket (verify count and drive type against Aston Martin documentation). Support the driveshaft end as you remove the final fasteners to prevent it from dropping. Note: At the rear transaxle, locate the driveshaft-to-transaxle flange fasteners. Verify the exact fastener count and drive type against Aston Martin service documentation before removal, then remove them while supporting the driveshaft end.
4. 4

   Remove front driveshaft connection
   At the front flange (engine/clutch housing end), remove the front driveshaft mounting fasteners. The DB9 front coupling is a flexible coupling disc bolted between the engine/flywheel flange and the torque tube shaft. Consult the Aston Martin workshop manual for the exact coupling type, fastener count, and drive size before removal. Carefully disengage the coupling per the manual while keeping the assembly supported and level. Note: Inspect the front coupling and surrounding seals for any signs of leakage. Have a drain pan ready in case fluid is present. Note: At the front of the driveshaft, remove the fasteners securing the coupling to the engine/flywheel flange. Consult the Aston Martin workshop manual for the exact coupling type and fastener count before removal, then carefully disengage the driveshaft from the engine coupling. Note: At the forward end of the torque tube, remove the driveshaft-to-engine coupling fasteners. Verify the exact fastener count and connection type against Aston Martin documentation, then carefully disengage the driveshaft while supporting its weight. Note: Inspect the forward driveshaft/torque tube connection at the engine for any sealing surfaces. Have a drain pan ready in case of fluid seepage and inspect seals as applicable. Note: No transmission output slip yoke exists at the front on this layout (the gearbox is a rear-mounted transaxle). Inspect the front engine/flywheel coupling area for any fluid or seal leakage and have a drain pan ready as a precaution.
   ⚠A small amount of transmission fluid may drip from the output shaft if a slip yoke is used. Have a drain pan ready and inspect the output shaft seal.
5. 5

   Remove center support bearing (if equipped)
   The DB9 driveshaft runs inside a rigid torque tube with internal bearings. If service of the torque tube or its bearings is required, consult Aston Martin workshop documentation for the correct removal procedure and fastener specifications before proceeding. Note: The DB9 driveshaft runs inside a rigid torque tube connecting the front engine to the rear transaxle; it is supported by internal bearings within the torque tube rather than an external center support bearing. Consult the Aston Martin workshop manual for torque tube removal and internal bearing servicing procedures specific to this chassis. Note: The DB9 driveshaft runs inside a rigid torque tube with internal bearings; there is no externally mounted center support bearing bracket. Follow Aston Martin procedures for torque tube support bearing service if required.
6. 6

   Remove driveshaft from vehicle
   Carefully lower the transmission jack and guide the driveshaft assembly out from under the vehicle. Keep the assembly level and supported at both ends to prevent damage to the flexible couplings or the torque tube internal bearings. Place the driveshaft on a clean workbench with the failed U-joint accessible. Inspect all components for wear, corrosion, or damage.
7. 7

   Remove U-joint snap rings
   Identify the failed U-joint on the driveshaft. This platform does not use a conventional cross-type U-joint with bearing caps and snap rings. If a flexible coupling disc is the failed component, follow the Aston Martin workshop manual to unbolt and replace the coupling disc as an assembly rather than pressing out bearing caps. Clean the snap ring grooves thoroughly and inspect for damage or wear that might prevent proper seating of new rings.
8. 8

   Press out old U-joint bearing caps
   If the driveshaft uses a serviceable cross-and-cap U-joint, use a U-joint pressing tool or hydraulic press to carefully press out the bearing caps from the yoke. Confirm with Aston Martin documentation that the joint is serviceable before attempting; some driveshafts require complete assembly replacement. Apply pressure to one bearing cap at a time, pressing it through the yoke ear until it can be removed. Rotate the U-joint cross and repeat for the remaining bearing caps. If a cap binds, tap the yoke lightly with a dead blow hammer while applying pressure. Remove the U-joint cross from the yoke once all bearing caps are out. Note: This procedure does not apply to the DB9 driveline. The flexible coupling disc is replaced as a bolted assembly, not pressed apart. Follow the Aston Martin workshop manual for coupling disc removal and torque-tube internal bearing service.
9. 9

   Clean yoke and inspect for damage
   Thoroughly clean the yoke ears and bearing cap bores with solvent and a wire brush. Inspect the yoke for cracks, elongated bearing cap bores, or other damage. Check that snap ring grooves are clean and undamaged. If the yoke shows significant wear or damage, the driveshaft assembly must be replaced rather than just the U-joint.
10. 10

    Install new U-joint bearing caps
    This procedure does not apply to the DB9 driveline. Install the new flexible coupling disc assembly per the Aston Martin workshop manual, torquing coupling fasteners to the specified values. Position the cross so one pair of trunnions aligns with the bearing cap bores. Start one bearing cap into its bore by hand, ensuring the needle bearings remain in place. Using the press or U-joint tool, carefully press the bearing cap into the yoke until the snap ring groove is visible. Install the snap ring, then repeat for the opposite bearing cap on the same axis. Rotate the cross 90 degrees and install the remaining two bearing caps and snap rings. Ensure all snap rings are fully seated in their grooves.
11. 11

    Verify U-joint installation and movement
    After all snap rings are installed, check that the U-joint moves freely in all directions without binding. There should be no perceptible play between the bearing caps and yoke. Rotate the U-joint through its full range of motion to ensure proper installation. If binding occurs, disassemble and inspect for misaligned needle bearings or debris.
12. 12

    Install driveshaft assembly into vehicle
    With the driveshaft repaired, position it on the transmission jack and raise it into position under the vehicle. If equipped with a center support bearing, align the bearing bracket with its mounting location and install the mounting fasteners finger-tight. Guide the front of the shaft/torque tube to the engine/flywheel coupling flange, aligning the marks made during removal. Install the front mounting fasteners finger-tight.
13. 13

    Connect rear driveshaft to differential
    Align the rear coupling with the transaxle input flange, carefully matching the phasing marks made during removal. Install the flexible coupling fasteners per the Aston Martin workshop manual, starting all fasteners finger-tight to ensure proper alignment before final tightening. Install all 4 strap bolts finger-tight initially to ensure proper alignment before final tightening.
    Torque spec

    Driveshaft U-Joint Straps20 Nm (15 lb-ft)
14. 14

    Torque all driveshaft fasteners
    Torque the rear coupling fasteners to the Aston Martin specified value in a criss-cross pattern to ensure even seating (verify torque against OEM workshop documentation). Note: this driveline has no slip-yoke 'yoke nut'; disregard any yoke-nut torque reference. Torque the front driveshaft coupling fasteners to the Aston Martin specified value for this chassis (verify in the workshop manual). If equipped with center support bearing, torque the bearing bracket mounting bolts to specification. Double-check that all alignment marks remain matched after torquing. Note: Torque the rear driveshaft coupling fasteners to the Aston Martin specified value for this chassis (verify in the workshop manual) in a criss-cross pattern to ensure even seating. Note: Torque the front driveshaft flange fasteners to the Aston Martin specified value (verify torque against OEM workshop documentation). Note: Torque the rear driveshaft flange/strap fasteners to Aston Martin specification in a criss-cross pattern to ensure even seating (verify exact value against factory documentation). Note: Torque the forward driveshaft coupling fasteners to Aston Martin specification (verify exact value against factory documentation).
    Torque spec

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

    Yoke Nut150 Nm (111 lb-ft)
15. 15

    Reinstall wheels and lower vehicle
    Reinstall the rear wheels and torque the wheel bolts to the Aston Martin specified value in a star pattern (verify exact value in the workshop manual before final tightening). Remove the transmission jack and supports. Carefully lower the vehicle to the ground. Perform a final visual inspection of all driveshaft connections to ensure nothing was missed. Note: Reinstall the rear wheels and torque the lug nuts/bolts to the Aston Martin specified value (approximately 150 Nm / 111 lb-ft — verify against OEM documentation) in a star pattern. Note: Reinstall the rear wheels and torque the lug fasteners to Aston Martin specification (typically around 150 Nm / 111 lb-ft) in a star pattern; verify the exact value against factory documentation.
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)

Reassembly

1. Ensure all phasing marks remain aligned after torquing all fasteners.
2. Verify that center support bearing (if equipped) sits flush in its mounting bracket with no visible offset.
3. Check that no tools, rags, or parts were left under the vehicle.

Verification

• Start the engine with the parking brake engaged and transmission in neutral. Listen for any unusual noises from the driveline.
• Test drive the vehicle at various speeds (30 mph, 50 mph, 70 mph) and note any vibrations. Properly phased and balanced driveshafts should produce no perceptible vibration.
• If vibration is present, re-check all alignment marks and fastener torque. Severe vibration may indicate incorrect phasing or a bent driveshaft requiring replacement.
• Inspect all driveshaft connections after the test drive for any signs of loosening or leakage.
• If a dial indicator is available, check driveshaft runout at the center. Runout should not exceed 0.030 inches (0.76 mm) for smooth operation.

More procedures for this vehicle