This procedure covers the replacement of the overdrive solenoid in the 10R80 automatic transmission found in 2021-2024 Ford F-150 3.5L EcoBoost RWD models.

Warnings

Tools required

Parts

• Overdrive solenoid (10R80 transmission) × 1 — Use OEM specification
• Transmission pan gasket × 1 — Use OEM specification
• Transmission filter × 1 — Use OEM specification
• Transmission drain plug crush washer × 1 — Use OEM specification

Fluids

• Motorcraft MERCON LV ATF — 6 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow transmission to cool completely if vehicle was recently operated
3. Disconnect negative battery cable to prevent electrical shorts during connector work
4. Raise vehicle on lift or support securely on jack stands at frame contact points
5. Remove engine belly pan and heat shields if equipped for transmission access
6. Place drain pan under transmission pan area

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission drain plug on the bottom of the transmission pan. Remove the drain plug and allow fluid to drain completely into the drain pan. Inspect drained fluid for metal particles or debris indicating internal wear. Remove and discard the old crush washer from the drain plug.
2. 2

   Remove transmission pan
   Remove all transmission pan bolts in a criss-cross pattern, starting from the center and working outward. Carefully lower the pan, being aware that residual fluid will spill. Inspect pan for debris or metal shavings. Clean the pan thoroughly with brake cleaner and inspect the magnet for abnormal metal accumulation.
3. 3

   Remove transmission filter
   Locate and remove the internal transmission filter. On the 10R80, the filter is typically secured with bolts or clips. Remove fasteners and carefully pull the filter straight down to avoid damaging the seal surface. Inspect the old filter for debris and clean the filter mounting surface on the valve body.
4. 4

   Access solenoid body assembly
   Locate the transmission control solenoid body on the valve body assembly. This is visible once the pan and filter are removed. Identify the electrical connectors leading to the solenoid body. Use a digital multimeter to verify the overdrive solenoid circuit before removal by checking resistance values against Ford specifications (typically 3-7 ohms).
5. 5

   Disconnect electrical connectors
   Carefully disconnect the main transmission control module connector(s) from the solenoid body. Note the routing and orientation of wiring harnesses. Use electrical connector picks if necessary to release locking tabs. Inspect connector pins for corrosion or damage.
6. 6

   Remove solenoid body cover
   Remove the solenoid body cover screws in sequence. The 10R80 typically has 8-12 screws securing the cover. Keep screws organized and note their positions as some may be different lengths. Carefully lift the cover to expose the individual solenoids.
   Torque spec

   Cover Screws12 Nm (9 lb-ft)
7. 7

   Remove overdrive solenoid
   Identify the overdrive solenoid within the solenoid body assembly (consult Ford service manual for exact location as it varies by transmission configuration). Remove the retaining bolt or clip securing the solenoid. Carefully extract the solenoid by pulling straight out. Inspect the solenoid bore and O-ring sealing surfaces for damage or scoring.
   ⚠Do not pry against aluminum valve body surfaces as this can cause permanent damage requiring valve body replacement.
8. 8

   Install new overdrive solenoid
   Lubricate the new solenoid O-rings with clean MERCON LV fluid. Carefully insert the new overdrive solenoid into the valve body bore, ensuring proper alignment. Push firmly until fully seated. Install the retaining bolt or clip and secure according to manufacturer specifications.
   Torque spec

   Sensor Bolts12 Nm (9 lb-ft)
9. 9

   Reinstall solenoid body cover
   Clean the solenoid body cover mating surface and inspect the gasket or O-ring seal. Install a new seal if damaged. Position the cover carefully and install all cover screws finger-tight first. Torque screws in a criss-cross pattern to specification.
   Torque spec

   Cover Screws12 Nm (9 lb-ft)
10. 10

    Reconnect electrical connectors
    Reconnect all electrical connectors to the solenoid body, ensuring they click into place and are fully seated. Verify proper routing of wiring harnesses to avoid pinch points when the pan is reinstalled.
11. 11

    Install new transmission filter
    Install the new transmission filter with a new seal or O-ring. Ensure the filter is properly seated and secure all mounting fasteners. Verify the filter sits flush against the valve body.
12. 12

    Reinstall transmission pan
    Clean the transmission pan mating surface on the transmission case thoroughly, removing all old gasket material. Install the new transmission pan gasket, ensuring proper alignment with all bolt holes. Position the pan carefully and install all pan bolts finger-tight. Torque bolts in a criss-cross pattern starting from the center.
    Torque spec

    Pan Bolts19 Nm (14 lb-ft)
13. 13

    Install drain plug and refill transmission
    Install a new crush washer on the drain plug. Thread the drain plug in by hand to avoid cross-threading, then torque to specification. Locate the transmission fill plug (typically on the side of the transmission case). Remove the fill plug and use a fluid pump to add approximately 5-6 quarts of MERCON LV fluid through the fill hole.
    Torque spec

    Drain Plug39 Nm (29 lb-ft)
14. 14

    Final fluid level adjustment
    Reinstall the fill plug to specification. Reconnect the battery negative cable. Start the engine and allow it to reach operating temperature with the vehicle on level ground. Cycle through all gear positions, pausing 2-3 seconds in each. With the engine running and transmission in Park, remove the fill plug. Fluid should drip slowly from the fill hole when at proper level. Add fluid as needed until a slow drip is achieved, then reinstall fill plug.
    ⚠️Keep hands and tools clear of moving drivetrain components while engine is running.
    Torque spec

    Fill Plug39 Nm (29 lb-ft)

Reassembly

1. Reinstall any belly pans or heat shields removed during preparation
2. Lower vehicle from lift or jack stands
3. Perform a final visual inspection under the vehicle for fluid leaks after 10 minutes of operation

Verification

• Test drive the vehicle through all gears, paying specific attention to overdrive engagement and shift quality
• Monitor for transmission warning lights or error codes using an OBD-II scanner
• Verify smooth shifting between all gears without slipping or harsh engagement
• Recheck transmission fluid level after test drive and top off if necessary
• Inspect for fluid leaks at the pan gasket and drain plug after test drive
• Clear any stored transmission codes if solenoid replacement resolves the issue, and verify no new codes set after test drive

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