This procedure covers the removal and replacement of the transmission oil cooler on a 2021-2024 Ford F-150 with 3.5L EcoBoost engine and RWD configuration.

Warnings

Tools required

Parts

• Transmission oil cooler × 1 — Use OEM specification
• Transmission oil cooler line O-rings × 4 — Use OEM specification
• Transmission fluid × 1 — Motorcraft MERCON LV ATF
• Transmission drain plug crush washer × 1 — Use OEM specification if equipped

Fluids

• Motorcraft MERCON LV ATF — 3 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine and transmission to cool completely if recently operated
3. Raise front of vehicle and secure on jack stands at frame contact points
4. Remove engine under-shield if equipped using 10mm fasteners
5. Place drain pan underneath transmission pan area
6. Mark transmission fluid level by checking dipstick or level plug if accessible for reference

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission drain plug on the bottom of the transmission pan. Position drain pan directly underneath. Remove drain plug using 13mm socket and allow fluid to drain completely. Inspect drain plug washer and replace if damaged. Reinstall drain plug with new washer.
   Torque spec

   Drain Plug39 Nm (29 lb-ft)
2. 2

   Remove front grille assembly
   Open hood and locate grille mounting points. Remove upper grille clips and push pins. Remove lower grille mounting bolts using 10mm socket. Carefully pull grille forward to release retention tabs. Disconnect any electrical connectors for grille lights or sensors if equipped. Set grille aside in safe location.
3. 3

   Access transmission oil cooler
   With grille removed, locate transmission oil cooler mounted in front of radiator assembly. Identify inlet and outlet transmission cooler lines routing from transmission to cooler. Note routing and position of lines for reinstallation. Take photos if needed for reference.
4. 4

   Disconnect transmission cooler lines
   Place drain pan underneath cooler line connections to catch residual fluid. Use appropriate quick-disconnect tool to release cooler line fittings at the transmission oil cooler. Gently pull lines free from cooler. Plug or cap open line ends immediately to prevent contamination. Expect approximately 0.5-1 quart of fluid to drain from lines.
   ⚠Do not pull on hard lines without releasing quick-disconnect fittings. Forcing connections will damage fittings and require line replacement.
5. 5

   Remove transmission oil cooler mounting hardware
   Locate transmission oil cooler mounting bolts securing cooler to radiator support or condenser bracket. On this model, cooler is typically secured with 2-4 mounting bolts. Remove mounting bolts using 10mm socket. Support cooler while removing final bolt to prevent dropping.
6. 6

   Remove transmission oil cooler
   Carefully tilt and maneuver transmission oil cooler free from mounting position. Be cautious of any remaining fluid draining from cooler. Inspect cooler mounting brackets and rubber isolators for damage. Clean mounting surface area on radiator support removing any debris or old gasket material.
7. 7

   Prepare new transmission oil cooler
   Unpack new transmission oil cooler and verify correct part number matches original. Install new O-rings on cooler inlet and outlet ports. Lubricate O-rings lightly with fresh MERCON LV ATF to aid installation and prevent damage. Verify mounting brackets are properly positioned on new cooler.
8. 8

   Install new transmission oil cooler
   Position new transmission oil cooler into mounting location, aligning with mounting holes on radiator support. Install mounting bolts finger-tight initially to allow adjustment. Verify cooler sits flush and properly aligned before final tightening. Torque mounting bolts evenly to specification.
   ℹ️Multiple mounting bolt torque values listed in database. Use 31 Nm (23 lb-ft) for transmission cooler mounting unless larger fasteners are present.
   Torque spec

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

   Reconnect transmission cooler lines
   Remove caps or plugs from transmission cooler lines. Inspect line fittings and replace O-rings if damaged or dried out. Insert cooler lines into new cooler ports ensuring proper orientation matches original configuration. Push firmly until quick-disconnect fittings click into locked position. Tug gently on each line to verify secure connection.
10. 10

    Reinstall front grille assembly
    Reconnect any electrical connectors for grille-mounted lights or sensors. Position grille assembly aligning lower mounting points first. Install lower grille mounting bolts finger-tight. Align upper grille clips and press firmly until seated. Install upper push pins and clips. Tighten lower mounting bolts using 10mm socket.
11. 11

    Refill transmission fluid
    Locate transmission fill tube or fill plug. Using transmission funnel and fluid transfer pump if needed, add approximately 3 quarts of Motorcraft MERCON LV ATF. Start with conservative amount as exact quantity depends on fluid lost during cooler removal. Do not overfill at this stage.
12. 12

    Check fluid level and circulation
    Start engine and allow to idle. With parking brake engaged and foot on brake pedal, shift transmission through all gear positions, pausing 2-3 seconds in each position. Return to Park. Check fluid level using dipstick or level plug method per Ford specification. Add fluid as needed to bring to proper level. Recheck transmission drain plug for leaks.

Reassembly

1. Reinstall engine under-shield if equipped, torquing fasteners to specification
2. Lower vehicle from jack stands and perform final fluid level check with vehicle on level ground
3. Verify all tools and parts have been removed from engine bay
4. Close hood and verify grille assembly is properly secured

Verification

• Start engine and visually inspect transmission oil cooler connections for leaks while engine idles
• Check transmission cooler lines at both transmission and cooler for any seepage
• Take short test drive (5-10 minutes) bringing transmission to operating temperature
• Recheck transmission fluid level when hot per manufacturer procedure and adjust if necessary
• Inspect under vehicle for any transmission fluid drips or leaks at drain plug and cooler lines
• Verify transmission shifts smoothly through all gears without slipping or harsh engagement

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