Transmission Flush

Complete transmission fluid exchange procedure for the 2009 Aston Martin DB9 with ZF 6-speed automatic transmission, including drain, pan removal, filter replacement, refill, and level verification.

Warnings

Tools required

Parts

• Transmission oil pan gasket × 1 — Use OEM Aston Martin specification
• Transmission filter kit (includes filter and O-rings) × 1 — Use OEM Aston Martin specification
• Transmission drain plug crush washer (if equipped) × 1 — Copper or aluminum sealing washer
• Transmission pan bolts (if reuse not recommended) × 1 — Use OEM specification or check condition

Fluids

• Touchtronic 6-speed ZF ATF — 9.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Verify level surface with spirit level if available.
2. Allow transmission to cool completely (minimum 2 hours after operation).
3. Raise vehicle on lift or support securely on jack stands at manufacturer jacking points. Ensure vehicle is level for accurate fluid level setting.
4. Remove engine undertray and transmission access panels. Undertray secured with multiple Torx fasteners around perimeter.
5. Locate transmission oil pan, drain plug (if equipped), and fill point. On DB9, fill point may be dipstick tube or fill plug on transmission case.
6. Place large drain pan (12+ quart capacity) beneath transmission oil pan.

Procedure

1. 1

   Drain transmission fluid via drain plug
   If transmission pan has drain plug, remove drain plug using appropriate socket. Allow fluid to drain completely into collection pan (approximately 3-4 quarts will drain initially — verify against Aston Martin service data). Inspect drain plug for metal particles or debris indicating internal wear. If a drain plug is fitted, remove and discard its sealing washer; note that the ZF 6HP26 pan on this vehicle may not have a conventional drain plug and draining may require pan removal or the fill-tube method.
2. 2

   Remove transmission oil pan bolts
   Locate all transmission pan bolts around perimeter (verify exact count against Aston Martin/ZF service data for the ZF 6HP26). Using the correct Torx bit (verify size against OEM spec), loosen all pan bolts in criss-cross pattern, loosening each 2-3 turns before moving to next bolt. Leave two bolts at opposite corners partially threaded to support pan weight. Gradually remove remaining bolts while supporting pan by hand. Note: Using the correct Torx bit (verify size against Aston Martin/ZF service data, commonly external Torx (E-Torx, e.g. E10/E12) on ZF 6HP26 pans — verify size and drive type against Aston Martin/ZF service data), loosen all pan bolts in criss-cross pattern, loosening each 2-3 turns before moving to next bolt.
3. 3

   Lower and drain transmission pan
   Carefully lower one corner of transmission pan to allow remaining fluid to drain into collection pan. Once fluid flow stops, remove final two support bolts and lower pan completely. Expect additional 1-2 quarts of fluid spillage. Keep pan level during removal to minimize spillage. Set pan aside on clean work surface.
4. 4

   Inspect pan and magnet for debris
   Inspect inside of transmission pan for metal shavings, friction material, or excessive debris. Small amount of fine metallic residue on magnet is normal. Large chunks, excessive material, or aluminum particles indicate internal transmission wear requiring further diagnosis. Clean pan thoroughly with brake cleaner and lint-free rags. Clean magnet completely.
5. 5

   Remove transmission filter
   Locate transmission filter inside transmission case (typically 3-4 bolts or snap-fit design securing filter). If bolted, remove filter mounting bolts using Torx bit. If snap-fit, carefully pry filter downward while twisting slightly to release from valve body. Note orientation and positioning of filter for reinstallation. Inspect filter O-rings and sealing surfaces.
6. 6

   Clean transmission pan mating surface
   Using plastic scraper or wire brush, carefully remove all old gasket material from transmission case mating surface. Do not gouge or scratch aluminum sealing surface. Clean surface thoroughly with brake cleaner and lint-free cloth. Ensure no gasket fragments fall into transmission case opening. Inspect mating surface for warping or damage.
7. 7

   Install new transmission filter
   Install new O-rings onto new transmission filter (included in filter kit). Lubricate O-rings lightly with clean ATF. Position new filter in same orientation as removed filter. The ZF 6HP26 filter is typically a press-fit cartridge (often integrated into the pan on later versions); press the new filter firmly into the valve body until the O-ring seats fully. If a bolted filter is fitted, verify bolt torque against Aston Martin/ZF service data. If snap-fit, press filter firmly into valve body until fully seated and locking tabs engage. Note: The ZF 6HP26 filter is a press/snap-fit design — press filter firmly into position until fully seated. Verify retention method and any torque spec against Aston Martin/ZF service data.
8. 8

   Install new pan gasket and refit pan
   Position new transmission pan gasket onto pan (gasket may have adhesive backing or require gasket adhesive for positioning). Align pan with transmission case, ensuring gasket remains properly positioned. Start all pan bolts by hand, threading each 2-3 turns before moving to next bolt to ensure proper alignment. Do not cross-thread aluminum case threads.
9. 9

   Torque transmission pan bolts
   Using torque wrench, tighten all transmission pan bolts in criss-cross pattern starting from center and working outward. Torque bolts to specification in multiple passes (first pass 50%, second pass 75%, third pass 100%) to ensure even gasket compression and prevent warping. Final torque specification is critical for proper sealing.
   Torque spec

   Transmission Pan Bolts12 Nm (9 lb-ft)
10. 10

    Install drain plug with new crush washer
    If transmission has drain plug, install new crush washer onto drain plug. Thread drain plug into pan by hand until snug, then torque to specification using torque wrench. Proper torque is critical to prevent leaks while avoiding thread damage to aluminum pan.
    Torque spec

    Transmission Drain Plug35 Nm (26 lb-ft)
11. 11

    Add initial transmission fluid charge
    Locate the transmission fill/level plug on the transmission pan (the ZF 6HP26 uses a fill/level plug with an internal overflow standpipe, not a dipstick). Using a fluid transfer pump with the appropriate adapter, add approximately 5 quarts of ZF Lifeguard 6 ATF through the fill/level plug located on the transmission pan (the ZF 6HP26 is a sealed design filled through the level plug and set by the overflow method; there is no dipstick). This represents approximate amount drained from pan and filter change. Pour slowly to prevent overflow and allow fluid to settle into transmission. Note: add approximately 5 quarts of ZF Lifeguard 6 ATF (JWS 3309 spec) through fill point Note: Using fluid transfer pump with appropriate adapter, add approximately 5 quarts of ZF Lifeguard 6 ATF through fill point.
12. 12

    Start engine and circulate fluid
    Start engine and allow to idle in Park. Fluid pump will begin circulating new fluid through transmission. Allow engine to idle for 2-3 minutes, then slowly cycle through all gear positions (P-R-N-D-S and back to P), pausing 3-5 seconds in each position. This fills torque converter and transmission passages with new fluid. Return to Park and allow to idle.
13. 13

    Check fluid level and add to specification
    With engine idling and transmission in Park, check fluid level through the fill/level plug opening on the pan. Transmission fluid must reach proper level at specific temperature range (35-45°C / 95-113°F measured with OBD-II scanner or fluid temperature gauge). Add fluid in 0.5 quart increments, rechecking level after each addition. Total dry-fill system capacity is approximately 9.5–10 quarts; however a pan-drop/filter service typically only requires a refill of the ~5–6 quarts removed, with exact amount set by level-plug method. Continue adding until fluid level reaches proper mark at specified temperature.
14. 14

    Perform final fluid level verification
    With transmission at the specified fluid temperature (approximately 30-50°C / 86-122°F), perform final level check via the fill/level plug: the level is correct when fluid stops running out as a steady stream and reduces to a slow drip, then install the plug. If using fill plug method, fluid level is correct when small amount of fluid begins to drip from fill plug opening with engine idling. Install the fill/level plug with a new sealing washer when the level is verified correct.

Reassembly

1. Reinstall transmission access panels and engine undertray using all original Torx fasteners.
2. Verify no tools or materials remain in engine bay or under vehicle.
3. Lower vehicle from lift or jack stands.
4. Start engine and verify no fluid leaks from transmission pan, drain plug, or fill point.
5. Test drive vehicle through all gears to verify proper shift quality and transmission operation.
6. Recheck fluid level after test drive when transmission reaches normal operating temperature.
7. Inspect under vehicle after 50-100 miles of operation to verify no delayed leaks from pan gasket.

Verification

• Verify no transmission fluid leaks from pan gasket, drain plug, or fill plug after engine reaches operating temperature.
• Verify smooth shifts through all gear ranges (Park, Reverse, Neutral, Drive, Sport) with no flare, harshness, or delay.
• Verify transmission fluid level is correct at operating temperature (35-45°C) using dipstick or fill plug method.
• Verify clean appearance of fresh ATF on dipstick (bright red color, no burnt smell).
• Monitor transmission behavior over next 100 miles for any shift quality changes that might indicate incorrect fluid level or air in system.

Related trouble codes on this vehicle

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