Transmission Fluid Change

This procedure drains and refills the 7-speed automatic transmission fluid (ATF 134) on the Mercedes-Benz S65 AMG, ensuring proper lubrication and transmission longevity.

Warnings

Tools required

Parts

• Transmission drain plug crush washer × 1 — A001 997 15 48
• Transmission pan gasket × 1 — Use OEM specification
• Transmission filter (if servicing) × 1 — 722.9 filter kit recommended

Fluids

• Mercedes-Benz ATF 134 — 6 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Start engine and allow transmission to reach normal operating temperature (10-15 minute drive).
3. Lift vehicle using approved jacking points and support securely on jack stands.
4. Remove engine/transmission undertray panels using T30 Torx or 10mm fasteners as equipped.
5. Connect diagnostic scan tool to read transmission fluid temperature during procedure.
6. Locate transmission drain plug on bottom of pan and fill plug on driver's side of transmission housing.

Procedure

1. 1

   Drain transmission fluid
   Position drain pan under transmission drain plug. Using 14mm socket, carefully loosen and remove drain plug. Allow fluid to drain completely (approximately 5-6 quarts will drain). Inspect drained fluid for metal particles or burning smell indicating internal wear. Remove and discard old crush washer from drain plug.
2. 2

   Reinstall drain plug with new washer
   Install new crush washer onto drain plug. Thread drain plug into transmission pan by hand to prevent cross-threading. Torque drain plug to specification using torque wrench.
   Torque spec

   Transmission Drain Plug30 Nm (22 lb-ft)
3. 3

   Remove transmission fill plug
   Locate fill/check plug on driver's side of transmission case (approximately mid-height). Using 14mm socket, remove fill plug. This will be used for both filling and level verification. Clean area around fill plug to prevent contamination.
4. 4

   Fill transmission with new ATF 134
   Using transmission fluid pump connected to fill plug opening, pump approximately 5.5 quarts of fresh Mercedes-Benz ATF 134 into transmission. Fill slowly to prevent air pockets. Stop when fluid begins to drip from fill hole. Leave fill plug removed for now.
5. 5

   Start engine and circulate fluid
   Start engine and allow to idle. With foot on brake, shift transmission through all gear positions (P-R-N-D-S), pausing 3-5 seconds in each position. Return to Park. Keep engine running throughout fluid level check process.
   ⚠Ensure vehicle is securely supported on jack stands and parking brake is engaged before running engine with vehicle elevated.
6. 6

   Check transmission fluid temperature
   Using diagnostic scan tool, monitor transmission fluid temperature. Fluid must be between 80°C and 100°C (176°F to 212°F) for accurate level check. Allow engine to idle until temperature is within this range. On M275 engine in S65 AMG, this typically takes 8-12 minutes of idling.
7. 7

   Verify fluid level at operating temperature
   With engine running, transmission in Park, and fluid at correct temperature (80-100°C), observe fill hole. Fluid should drip slowly from fill hole opening (approximately 1 drip per second). If no fluid drips, add ATF in small increments until slow drip is achieved. If fluid streams out, too much fluid is present and must be drained to correct level.
   ⚠Fluid dripping from fill hole will be at operating temperature (80-100°C). Use caution to avoid burns.
8. 8

   Install fill plug
   Once correct fluid level is verified (slow drip from fill hole), quickly install fill plug while engine is still running. Hand-thread plug carefully, then torque to 30 Nm (22 lb-ft) - same specification as drain plug.
   Torque spec

   Transmission Drain Plug30 Nm (22 lb-ft)
9. 9

   Final system check
   Turn off engine. Lower vehicle from jack stands. Reinstall undertray panels and torque fasteners appropriately. Start engine and verify no leaks from drain or fill plug. Test drive vehicle through all gears, verifying smooth shifting with no slipping or harsh engagements.

Reassembly

1. Reinstall all undertray panels in reverse order of removal.
2. Reset transmission adaptation values using diagnostic scan tool if recommended by Mercedes-Benz procedures for your model year.
3. Record mileage and date of service for maintenance tracking.

Verification

• Check for fluid leaks around drain plug and fill plug after test drive.
• Verify smooth transmission operation in all gear ranges with no slipping, harsh shifts, or delayed engagement.
• Confirm transmission fluid temperature reaches normal operating range (80-100°C) during test drive.
• Use scan tool to verify no transmission fault codes are present after service.
• Recheck fluid level at operating temperature after initial test drive to ensure accuracy.

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