transmission

Transmission Speed Sensor - Input

for 2021 Ford F-150 3.5L V6 EcoBoost · 4WD

Difficulty

Moderate

Time

1.2 h

Tools

Steps

This procedure covers the removal and replacement of the input speed sensor on the 10R80 automatic transmission in a 2021-2024 Ford F-150 with the 3.5L EcoBoost V6 engine.

Warnings

⚠The transmission must be at operating temperature for proper fluid level check. Hot transmission fluid can cause severe burns.

⚠Ensure the vehicle is securely supported on jack stands before working underneath. Never rely solely on a hydraulic jack.

ℹ️The input speed sensor is located on the passenger side of the transmission case, near the bell housing area.

ℹ️Some transmission fluid will drain when the sensor is removed. Have a drain pan ready.

Tools required

10mm socket and ratchetEssential

Torque wrench (5-25 Nm range)Essential

Trim panel removal tools

Drain pan (minimum 2 quart capacity)Essential

Shop towels or ragsEssential

Vehicle jack and jack standsEssential

Wheel chocksEssential

Funnel for transmission fluidEssential

Transmission fluid pump or fill bottleEssential

Flashlight or work lightEssential

Parts

Transmission input speed sensor × 1 — Use OEM specification
Sensor O-ring seal × 1 — Often included with sensor

Fluids

Motorcraft MERCON LV ATF — 1.5 qt

Preparation

Park vehicle on level ground and apply parking brake
Place wheel chocks behind rear wheels
Allow engine and transmission to cool if recently driven
Raise front of vehicle and support securely on jack stands
Remove plastic under-shield or belly pan if equipped to access transmission
Locate the input speed sensor on the passenger side of the transmission near the front bell housing section

Procedure

1
Disconnect electrical connector
Locate the input speed sensor electrical connector. Press the locking tab and carefully disconnect the wiring harness connector from the sensor. Inspect the connector pins for corrosion or damage.
2
Position drain pan
Place a drain pan directly beneath the input speed sensor location. Approximately 1-2 quarts of transmission fluid may drain when the sensor is removed.
3
Remove sensor retaining bolt
Using a 10mm socket, remove the single retaining bolt securing the input speed sensor to the transmission case. Keep the bolt in a safe location for reinstallation.
Torque spec
Sensor Bolts12 Nm (9 lb-ft)
4
Extract sensor from transmission
Carefully pull the sensor straight out of the transmission case bore. Avoid tilting or twisting the sensor excessively. Allow residual fluid to drain into the pan. Remove and discard the old O-ring seal from the sensor body.
5
Inspect transmission bore
Inspect the sensor bore in the transmission case for debris, metal shavings, or damage. Wipe the mounting surface clean with a shop towel. Check that no foreign material has entered the transmission.
6
Prepare new sensor
Install the new O-ring seal onto the new sensor body. Lightly lubricate the O-ring with clean MERCON LV transmission fluid to aid installation and prevent seal damage.
7
Install new sensor
Carefully insert the new input speed sensor straight into the transmission case bore, ensuring the O-ring does not roll or pinch. Push the sensor in until it is fully seated against the transmission case.
8
Install and torque retaining bolt
Install the sensor retaining bolt and tighten by hand until snug. Using a torque wrench, tighten the bolt to specification. Do not overtighten as this can crack the sensor housing.
Torque spec
Sensor Bolts12 Nm (9 lb-ft)
9
Reconnect electrical connector
Reconnect the wiring harness connector to the sensor, ensuring it clicks into place and the locking tab is fully engaged. Gently tug on the connector to verify it is secure.
10
Refill transmission fluid
Using a fluid pump or fill bottle, add approximately 1.5 quarts of Motorcraft MERCON LV ATF through the transmission fill tube. The exact amount will depend on how much was lost during sensor removal.
11
Check fluid level
Start the engine and allow it to reach normal operating temperature. With the engine running and the transmission in Park on level ground, check the transmission fluid level using the dipstick. Add fluid as necessary to bring level to the proper range.
12
Reinstall under-shield
If removed, reinstall any plastic under-shields or belly pans that were removed for access. Lower the vehicle from jack stands.

Reassembly

Ensure all electrical connectors are fully seated and locked
Verify no tools or parts were left in the work area
Double-check that the sensor retaining bolt is properly torqued
Confirm transmission fluid level is correct with engine at operating temperature

Verification

Start the engine and verify no transmission fluid leaks from the sensor area
Use a scan tool to verify the input speed sensor is providing a signal to the PCM
Test drive the vehicle and confirm smooth shifting with no transmission-related fault codes
Recheck transmission fluid level after test drive and top off if necessary
Monitor for any illuminated warning lights on the instrument cluster