This procedure covers removal and replacement of the transmission oil cooler on a 2015-2020 Ford F-150 with 3.5L EcoBoost V6 engine and RWD configuration.

Warnings

Tools required

Parts

• Transmission oil cooler assembly × 1 — Use OEM specification
• Transmission cooler line O-rings × 4 — Use OEM specification
• Transmission oil cooler mounting bolts × 2 — Use OEM specification
• Transmission drain plug crush washer × 1 — Use OEM specification if equipped

Fluids

• Motorcraft MERCON LV ATF — 4 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine and transmission to cool completely (minimum 2 hours after operation)
3. Disconnect negative battery cable
4. Raise front of vehicle and support securely on jack stands
5. Remove engine skid plate if equipped
6. Place drain pans under transmission and radiator area

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission drain plug on the bottom of the transmission pan. Position drain pan underneath and remove drain plug using appropriate socket. Allow fluid to drain completely. Inspect drain plug and crush washer for damage.
   Torque spec

   Transmission Drain Plug30 Nm (22 lb-ft)
2. 2

   Access transmission oil cooler
   From underneath the vehicle, locate the transmission oil cooler mounted to the lower radiator support or frame rail. The cooler is positioned forward of the transmission with two cooler lines running to it. Remove any splash shields or guards blocking access to the cooler and mounting points.
3. 3

   Disconnect cooler inlet line
   Identify the transmission cooler inlet line (coming from transmission). Use appropriate line disconnect tool to release the quick-connect fitting at the cooler. Be prepared for residual fluid drainage. Cap or plug the line to prevent contamination.
   ⚠Residual transmission fluid under pressure may spray when disconnecting lines. Wear eye protection and have towels ready.
4. 4

   Disconnect cooler outlet line
   Use line disconnect tool to release the quick-connect fitting for the outlet line (returning to transmission) at the cooler. Allow any residual fluid to drain into pan. Cap or plug the line to prevent dirt intrusion and fluid loss.
5. 5

   Remove cooler mounting hardware
   Locate the two mounting bolts securing the transmission oil cooler to the frame rail or radiator support bracket. Remove both mounting bolts and retain for inspection. Note the orientation and position of any brackets or spacers.
6. 6

   Remove transmission oil cooler
   Carefully lower the transmission oil cooler from its mounting position. Maneuver the cooler away from the lines and frame, being careful not to damage radiator or AC condenser. Tilt cooler to drain any remaining fluid into drain pan. Inspect mounting location for debris or damage.
7. 7

   Prepare new transmission oil cooler
   Unpack new transmission oil cooler and verify it matches the original unit. Install new O-rings on both inlet and outlet ports of the new cooler. Lightly lubricate O-rings with clean MERCON LV ATF to ensure proper sealing. Inspect mounting brackets and transfer to new cooler if necessary.
8. 8

   Install new transmission oil cooler
   Position new transmission oil cooler into mounting location, ensuring proper alignment with cooler line connections and mounting holes. Verify O-rings are seated correctly in their grooves. Start both mounting bolts by hand to ensure proper thread engagement.
   ℹ️Verify which mounting bolt specification applies (23 lb-ft or 52 lb-ft) based on bolt size and location per service manual.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
9. 9

   Connect transmission cooler lines
   Remove caps from transmission cooler lines. Firmly push inlet line into cooler port until you hear/feel a distinct click indicating the quick-connect fitting is fully seated. Repeat for outlet line. Gently tug on each line to verify secure connection.
10. 10

    Reinstall drain plug and fill transmission
    Install new crush washer on transmission drain plug. Thread drain plug into transmission pan by hand, then tighten to specification. Remove transmission dipstick (if equipped) or access fill plug. Add approximately 4 quarts of Motorcraft MERCON LV ATF through fill point. Final level will be verified after circulation.
    Torque spec

    Transmission Drain Plug30 Nm (22 lb-ft)
11. 11

    Reinstall underbody components
    Reinstall engine skid plate if equipped. Verify all drain pans are removed from under vehicle. Lower vehicle from jack stands to ground. Reconnect negative battery cable.
12. 12

    Circulate fluid and verify level
    Start engine and allow to idle. Cycle transmission through all gear positions (Park, Reverse, Neutral, Drive, Low) holding each for 5 seconds. Return to Park. With engine at operating temperature and running, check transmission fluid level per manufacturer procedure. Add fluid as needed to achieve proper level on dipstick or until fluid appears at check plug.

Reassembly

1. Torque all fasteners to specifications using proper sequence where applicable
2. Ensure all quick-connect fittings are fully seated and secured
3. Verify no fluid leaks at cooler connections after initial circulation

Verification

• Start engine and verify no transmission fluid leaks at cooler or line connections
• Check transmission fluid level with engine at operating temperature per manufacturer specifications
• Test drive vehicle through all gears to verify proper transmission operation and shifting
• Recheck fluid level after test drive and top off if necessary
• Inspect underneath vehicle for any fluid drips or leaks after 24 hours of operation

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