This procedure covers the removal and replacement of the transmission oil cooler, including disconnecting cooler lines, draining transmission fluid, and refilling the system.

Warnings

Tools required

Parts

• Transmission oil cooler assembly × 1 — Use OEM specification
• Transmission cooler line O-rings × 1 — Replace all cooler line connections
• Transmission drain plug crush washer × 1 — Use OEM specification if equipped
• Shop towels × 1 — Generic

Fluids

• Motorcraft MERCON LV ATF — 4 qt

Preparation

1. Park vehicle on level ground and allow to cool completely for at least 2 hours
2. Engage parking brake and place wheel chocks behind rear wheels
3. Disconnect negative battery cable to prevent accidental engagement
4. Raise front of vehicle and support on jack stands rated for vehicle weight
5. Place drain pan underneath transmission
6. Remove front skid plate or belly pan if equipped

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission drain plug on the bottom of the transmission pan. Place drain pan underneath and remove drain plug using appropriate socket. Allow fluid to drain completely (approximately 5-7 minutes). If equipped with crush washer, discard old washer and prepare new one for installation. Reinstall drain plug with new washer.
   Torque spec

   Drain Plug42 Nm (31 lb-ft)
2. 2

   Locate transmission oil cooler
   The transmission oil cooler is mounted to the front of the radiator support on the driver side. Identify the two cooler lines running from the transmission to the cooler assembly. Note the routing and orientation of lines for reinstallation.
   ℹ️Take photos of line routing before removal to ensure correct reinstallation.
3. 3

   Disconnect lower cooler line
   Using the appropriate cooler line disconnect tool, release the quick-connect fitting on the lower transmission cooler line at the cooler. Have shop towels ready to catch residual fluid. Plug or cap the line to prevent contamination.
   ⚠Residual fluid will spray when line is disconnected. Ensure drain pan and towels are positioned to catch fluid.
4. 4

   Disconnect upper cooler line
   Using the cooler line disconnect tool, release the quick-connect fitting on the upper transmission cooler line at the cooler. Have shop towels ready to catch residual fluid. Plug or cap the line to prevent contamination.
   ⚠Upper line may contain more residual fluid than lower line.
5. 5

   Remove cooler mounting bolts
   Remove the mounting bolts securing the transmission oil cooler to the radiator support or frame bracket. On most 2015-2020 F-150 models, there are typically 2-4 mounting bolts. Support the cooler while removing the final bolt.
   Torque spec

   Mounting Bolts76 Nm (56 lb-ft)
6. 6

   Remove old cooler
   Carefully lower and remove the transmission oil cooler from the vehicle. Tilt as necessary to clear surrounding components. Inspect the cooler for leaks, damage, or debris that may have caused failure.
   ℹ️Inspect cooler lines and radiator for damage or debris while cooler is removed.
7. 7

   Prepare new cooler
   Remove new transmission oil cooler from packaging. Install new O-rings on all quick-connect fittings, ensuring they are properly seated in their grooves. Lightly lubricate O-rings with clean MERCON LV transmission fluid.
   ℹ️Do not use petroleum-based lubricants on O-rings. Use only transmission fluid.
8. 8

   Install new cooler
   Position the new transmission oil cooler in the mounting location, ensuring proper orientation. Thread mounting bolts by hand to avoid cross-threading. Tighten mounting bolts in a criss-cross pattern to specified torque.
   Torque spec

   Mounting Bolts76 Nm (56 lb-ft)
9. 9

   Reconnect cooler lines
   Remove plugs or caps from transmission cooler lines. Connect the lower cooler line to the cooler first, then the upper line. Push each fitting firmly until you hear and feel a click, indicating proper engagement. Pull gently on each line to verify secure connection.
   ⚠Ensure fittings click into place. Improper connection will cause fluid leaks and transmission damage.
10. 10

    Refill transmission fluid
    Using a funnel, add approximately 3-4 quarts of Motorcraft MERCON LV ATF through the transmission dipstick tube. Start engine and allow to idle in Park. With engine running, shift through all gear positions, pausing 2-3 seconds in each. Return to Park and check fluid level on dipstick with engine running. Add fluid as necessary to bring level to the cold range.
    ⚠Do not overfill transmission. Overfilling can cause foaming and transmission damage.
11. 11

    Check for leaks
    With engine running, inspect all cooler line connections and the cooler itself for signs of leakage. Visually inspect drain plug area. If leaks are present, shut off engine immediately and repair before proceeding.

Reassembly

1. Reinstall front skid plate or belly pan if equipped
2. Lower vehicle from jack stands
3. Reconnect negative battery cable
4. Remove wheel chocks

Verification

• Start engine and allow to reach normal operating temperature while monitoring for leaks
• With engine at operating temperature, recheck transmission fluid level and adjust as necessary to bring level to hot range on dipstick
• Test drive vehicle through all gears to verify proper transmission operation
• After test drive, recheck fluid level and inspect cooler area for any signs of leakage
• Monitor transmission fluid level and cooler area for leaks during the first 100 miles of operation

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