Replace the output shaft speed sensor on the 6R80 automatic transmission to restore speedometer function and transmission shift quality.

Warnings

Tools required

Parts

• Output shaft speed sensor (OSS) × 1 — Use OEM Ford sensor or equivalent
• O-ring seal for sensor × 1 — Often included with sensor

Fluids

• Motorcraft MERCON LV ATF — 0.5 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place wheel chocks behind rear wheels
3. Allow transmission to cool if vehicle was recently operated
4. Raise front of vehicle with floor jack and support on jack stands at frame rails
5. Verify vehicle is stable before working underneath

Procedure

1. 1

   Locate the output shaft speed sensor
   Position yourself under the passenger side of the transmission. The output shaft speed sensor is located on the rear passenger side of the transmission case, near the output shaft housing. It has a single electrical connector and is held by one 10mm bolt.
2. 2

   Disconnect the electrical connector
   Press the release tab on the sensor electrical connector and pull the connector straight away from the sensor. There may be a secondary locking tab that needs to be lifted before the connector will release. Do not pull on the wiring harness.
3. 3

   Position drain pan
   Place a drain pan or shop rags beneath the sensor location. When the sensor is removed, some transmission fluid will drain out, typically 4-8 ounces depending on fluid level.
4. 4

   Remove sensor mounting bolt
   Using a 10mm socket and ratchet, remove the single bolt securing the output shaft speed sensor to the transmission case. Keep the bolt for reinstallation.
   Torque spec

   Sensor Bolts14 Nm (10 lb-ft)
5. 5

   Extract the sensor
   Carefully pull the sensor straight out of the transmission case. If it is stuck, gently twist while pulling or use a small pry tool to help release it. Avoid damaging the sensor bore in the transmission case. Allow any residual fluid to drain into the pan.
6. 6

   Inspect and clean the sensor bore
   Examine the sensor mounting bore in the transmission case for debris or metal particles. Clean the area with a shop rag. Check the old sensor for metal shavings on the magnetic tip, which is normal but excessive buildup may indicate internal transmission wear.
7. 7

   Prepare new sensor
   Remove the new output shaft speed sensor from packaging. Verify it matches the old sensor. Inspect the new O-ring seal and lightly coat it with clean MERCON LV ATF. Do not use petroleum-based lubricants on the O-ring.
8. 8

   Install new sensor
   Carefully insert the new sensor into the transmission case bore, ensuring the O-ring does not get pinched or damaged. Push the sensor in until it is fully seated against the transmission case. The sensor should sit flush with minimal resistance.
9. 9

   Install and torque mounting bolt
   Thread the 10mm mounting bolt by hand to ensure proper thread engagement. Using a torque wrench, tighten the sensor bolt to 14.0 Nm (10.0 lb-ft). Do not overtighten as this can crack the sensor body.
   Torque spec

   Sensor Bolts14 Nm (10 lb-ft)
10. 10

    Reconnect electrical connector
    Push the electrical connector onto the new sensor until it clicks into place. Ensure the secondary locking tab (if equipped) is properly engaged. Gently tug on the connector to verify it is secure.
11. 11

    Check transmission fluid level
    Lower the vehicle to the ground. Start the engine and allow it to reach normal operating temperature. With the engine running and transmission in Park, check the fluid level using the dipstick (if equipped) or through the fill plug. Add MERCON LV ATF as needed to bring level to the correct range. Most fluid loss during this repair is minimal, typically 0.25-0.5 quarts.

Reassembly

1. Ensure electrical connector is fully seated and locked
2. Verify no transmission fluid leaks are present around sensor
3. Clear any diagnostic trouble codes from the PCM using a scan tool

Verification

• Start engine and verify no fluid leaks at sensor location
• Take vehicle for short test drive and confirm speedometer is functioning correctly
• Verify transmission shifts smoothly through all gears without harsh engagement
• Use scan tool to confirm OSS signal is being received by the PCM (should show speed when vehicle is moving)
• Recheck transmission fluid level after test drive and top off if necessary

More procedures for this vehicle