Shift Solenoid - Single

Remove and replace a single shift solenoid in the ZF 6-speed automatic transmission (Touchtronic) of the 2009 Aston Martin DB9, requiring pan removal and partial fluid drain.

Warnings

Tools required

Parts

• Shift solenoid (identify specific position before ordering) × 1 — Use OEM specification - varies by solenoid position
• Transmission pan gasket × 1 — Use OEM specification or equivalent
• Transmission drain plug crush washer × 1 — Copper or aluminum sealing washer
• Transmission filter (recommended replacement) × 1 — Use OEM specification

Fluids

• transmission_auto — 5 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Allow transmission to cool completely if vehicle has been operated (minimum 2 hours).
3. Raise vehicle on lift or support securely on jack stands at all four corners.
4. Remove engine undertray panels - typically secured with multiple Torx fasteners around perimeter.
5. Identify the failed solenoid position using diagnostic scan tool or service documentation before proceeding.
6. Have replacement solenoid, gasket, and fresh ATF ready before beginning disassembly.

Procedure

1. 1

   Drain transmission fluid
   Position drain pan beneath transmission. Locate the transmission drain plug (verify the DB9 ZF 6HP26 uses a combined drain/fill arrangement with an internal level standpipe — confirm plug type and location against service data before draining). Using appropriate socket, loosen drain plug slowly. Remove plug completely and allow fluid to drain fully (capture and measure the drained quantity to use as a refill reference; verify spec against service data). Inspect drained fluid for metal particles or burnt odor indicating additional transmission damage. Remove and discard the old drain plug seal (the ZF 6HP26 drain plug typically uses an O-ring rather than a crush washer — verify seal type against service data). Note: Remove plug completely and allow fluid to drain fully (drained quantity will vary; verify expected drain/fill volume against ZF 6HP26 capacity specifications).
2. 2

   Remove transmission pan
   With fluid drained, locate all transmission pan bolts around the perimeter (verify exact count against service documentation for your specific pan). Loosen all bolts evenly in several passes around the perimeter before fully removing to prevent distortion. Carefully lower pan - residual fluid will remain inside. Place pan on clean surface and inspect interior for metal debris or clutch material. Note that ZF 6HP26 filter arrangement varies by production variant: some use a separate serviceable filter, others integrate the filter into the pan assembly. Verify which arrangement applies to this specific transmission against service data and inspect/replace the filter or pan-filter unit accordingly. Note: On the ZF 6HP26 the oil filter is commonly integrated into the pan assembly; if the pan/filter unit shows contamination, replace the complete pan-and-filter assembly per OEM specification. Note: With fluid drained, locate all transmission pan bolts around perimeter (consult Aston Martin/ZF service data for exact count — the ZF 6HP26 pan type varies by variant (metal pan with separate filter, or plastic pan with integrated filter), so verify pan type and bolt count against service data). Loosen bolts evenly in a criss-cross/diagonal pattern across the perimeter in several passes to prevent pan warping. Note: If equipped with a serviceable filter, remove and inspect it - replace if contaminated. Note: many ZF 6HP26 applications use a pan with an integrated filter, in which case the entire pan/filter assembly is replaced as a unit. Note: With fluid drained, locate all transmission pan bolts around the perimeter (verify exact bolt count against Aston Martin/ZF service documentation for the ZF 6HP26 pan). Remove bolts in a criss-cross pattern starting from center and working outward to prevent pan warping.
   ⚠Approximately 1-2 quarts of fluid will remain in pan. Have drain pan positioned to catch spillage when pan is lowered.
3. 3

   Access valve body and locate target solenoid
   With pan removed, the valve body and solenoid pack are now visible. The ZF 6HP26 valve body carries multiple electro-hydraulic solenoids (verify exact count against ZF/Aston Martin service data). Reference your diagnostic data or service information to identify which specific solenoid requires replacement — the 6HP26 uses ZF pressure-regulating (EDS/VBS) and on/off solenoid designations rather than SAE 'shift solenoid A–E' labels. Take photograph of solenoid positions and wire harness routing for reinstallation reference. Note: The ZF 6HP26 valve body carries multiple shift and pressure-regulating (EDS) solenoids (verify exact count and designations against service data for this application). Note: Reference your diagnostic data or service information to identify which specific solenoid requires replacement (ZF designations such as the shift solenoids and the pressure-regulating EDS solenoids — identify the exact position from service data). Note: The ZF 6HP26 valve body contains multiple solenoids (a mix of pressure-regulating/EDS solenoids and shift/on-off solenoids); verify the exact solenoid count and ZF designation against service documentation. Reference your diagnostic data or service information to identify which specific solenoid requires replacement.
4. 4

   Disconnect solenoid electrical connector
   Locate the electrical connector for the target solenoid. ZF solenoids typically use individual connectors with sliding locks or squeeze-tab releases. Carefully press release tab or slide lock while pulling connector straight off solenoid. Do not pull on wires. Inspect connector pins for corrosion or damage. If connector is part of a harness bundle, note routing and any securing clips.
5. 5

   Remove failed solenoid
   ZF solenoids may be retained by a retaining plate, clip, or small screw(s) depending on position - confirm the exact retention method and fastener size against service documentation before removal. Remove the retaining bolts securing the solenoid to the valve body. Gently wiggle and pull the solenoid straight out from its bore in the valve body. Inspect O-rings on solenoid body - note their positions. If solenoid is stuck, do not pry against valve body casting - use gentle twisting motion only.
   ⚠Solenoid bore in valve body contains precision surfaces. Do not allow dirt or debris to enter bore. Cover opening with clean lint-free towel if there will be any delay before installation.
6. 6

   Clean solenoid mounting area
   Using clean solvent and lint-free towels, thoroughly clean the solenoid bore in the valve body. Remove any old seal material or debris. Inspect bore for scoring or damage. Clean the mating surface around the bore where solenoid flange seats. Ensure no cleaning solvent or debris remains in bore or fluid passages.
7. 7

   Prepare and install new solenoid
   Remove new solenoid from packaging. Verify it matches the failed unit (compare physical dimensions, connector type, and part number). Check that new O-rings are properly seated in grooves on solenoid body. Lightly lubricate O-rings with clean ATF. Align solenoid with bore and insert straight in - do not force. Seat solenoid fully until flange contacts valve body surface. Secure the solenoid using its correct retention method (many ZF 6HP26 solenoids use a spring retainer clip rather than Torx bolts — verify for your valve body). If bolted, torque to the exact ZF specification for that solenoid position. Note: Torque to the exact ZF specification for your specific solenoid and bracket (do not rely on a generic value — verify from service data before tightening these small fasteners, and note many 6HP26 solenoids use a spring retainer clip with no torque spec). Note: Torque to ZF specification (verify the exact torque for your specific solenoid fastener against ZF/Aston Martin service data before tightening; do not guess, as overtightening can damage the valve body casting).
8. 8

   Reconnect electrical connector
   Route solenoid wire harness as documented in your reference photo. Press electrical connector firmly onto solenoid until locking tab clicks into place. Verify connection is secure by gently tugging on connector body (not wires). Ensure harness has no sharp bends and does not contact any moving components or sharp edges.
9. 9

   Clean and prepare pan mating surfaces
   Thoroughly clean transmission pan interior and exterior. Remove all old gasket material from pan flange using plastic scraper - do not gouge aluminum surface. Clean transmission case pan sealing surface removing all old gasket material and residue. Both surfaces must be completely clean and dry for proper gasket seal. Inspect pan for cracks or damage, particularly around bolt holes.
10. 10

    Install new pan gasket and reinstall pan
    Position new transmission pan gasket onto pan or transmission case per gasket manufacturer instructions (some adhere to pan, others to case). Carefully lift pan into position, aligning gasket with case. Start all pan bolts by hand to ensure proper thread engagement and pan alignment. Once all bolts are started, tighten in criss-cross pattern from center outward in multiple passes.
    Torque spec

    Transmission Pan Bolts12 Nm (9 lb-ft)
11. 11

    Install drain plug and refill transmission
    Install a new drain plug seal (ZF 6HP26 plugs typically use an O-ring rather than a crush washer — verify correct seal type). Thread drain plug into pan by hand, then tighten to specification. Locate transmission fill plug or dipstick tube (consult service manual for fill procedure on ZF 6HP26 - some variants require fill from below through plug, others from dipstick tube). Using fluid transfer pump, add approximately the same quantity you captured during draining of ZF-approved ATF as an initial fill. Do not overfill at this stage. Note: Install a new sealing element on the drain plug (ZF 6HP26 plugs typically use an O-ring rather than a crush washer — verify correct seal type). Thread drain plug into pan by hand, then tighten to specification. Note: Using fluid transfer pump, add approximately the same quantity of ZF-approved ATF that was actually drained. Do not overfill at this stage; final level is set via the temperature-based level procedure.
    ⚠ZF 6HP26 transmission requires specific fill and level-check procedure at operating temperature. Initial fill quantity gets you close, but final level must be set with transmission at 40-50°C using prescribed procedure.
    Torque spec

    Transmission Drain Plug38 Nm (28 lb-ft)
12. 12

    Reinstall undertray and lower vehicle
    Reinstall engine undertray panels, ensuring all Torx fasteners are properly seated and tightened. Verify no tools or materials were left in engine bay or under vehicle. Lower vehicle to ground.
13. 13

    Perform transmission fluid level check procedure
    With vehicle on level ground, start engine and allow to reach operating temperature. Follow ZF-specific level check procedure: transmission must be at 40-50°C (use scan tool to monitor transmission temperature), run through all gear positions (P-R-N-D-S) pausing 3 seconds in each, return to Park. With engine running at idle, check fluid level per service manual procedure (dipstick reading or level plug method depending on variant). Add fluid as needed to reach proper level. Recheck after reaching full operating temperature.
14. 14

    Clear codes and perform adaptation
    Using appropriate diagnostic scan tool, clear any stored transmission fault codes. Perform transmission adaptation or re-learn procedure as specified by Aston Martin service procedures for the 2009 DB9. Some scan tools may require specific software to access Touchtronic transmission adaptation functions. If adaptation is not performed, transmission may exhibit harsh shifts until it self-adapts over normal driving cycles.

Reassembly

1. Transmission pan bolts must be torqued in criss-cross pattern to prevent gasket leaks and pan warping.
2. Final transmission fluid level can only be accurately checked at operating temperature using prescribed ZF procedure.
3. If transmission filter was replaced, add an additional 0.5 quarts of ATF to compensate for filter absorption.
4. Transmission adaptation procedure is critical for proper shift quality after solenoid replacement.

Verification

• Start engine and verify no transmission fluid leaks from pan or drain plug while engine idles.
• Using scan tool, verify the new solenoid is communicating properly and no fault codes are present for that solenoid position.
• Perform test drive including all gear ranges - verify smooth shifts with no harsh engagement or slipping.
• Verify transmission fluid level is correct at full operating temperature using ZF prescribed procedure.
• After test drive, re-inspect underneath vehicle for any signs of fluid leakage from pan gasket or drain plug.
• Monitor transmission behavior over first 50-100 miles - shifts should become progressively smoother as adaptation completes.

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle