This procedure covers the replacement of the output speed sensor on the 68RFE automatic transmission in a 2014 Ram 2500 with the 6.7L Cummins diesel engine.

Warnings

Tools required

Parts

• Output speed sensor × 1 — Mopar 5149148AA or equivalent
• O-ring for speed sensor × 1 — Usually included with sensor

Fluids

• Mopar ATF+4 — 1.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks behind rear wheels
3. Allow transmission and exhaust system to cool if vehicle was recently operated
4. Raise front of vehicle and secure on jack stands rated for vehicle weight
5. Remove driver side front wheel for improved access (optional but recommended)
6. Locate the output speed sensor on the rear driver side of the transmission case

Procedure

1. 1

   Access the output speed sensor
   From underneath the vehicle on the driver side, locate the output speed sensor mounted on the rear section of the transmission case, near the output shaft. The sensor has an electrical connector and is secured by a single bolt. You may need to trace the wiring harness from the transmission to locate it.
2. 2

   Disconnect electrical connector
   Press the tab on the electrical connector and carefully pull it away from the output speed sensor. If the connector is difficult to remove, gently work it side to side while pulling. Do not pull on the wiring harness itself.
3. 3

   Position drain pan
   Place a drain pan with at least 2 gallon capacity directly beneath the output speed sensor. Expect approximately 0.5 to 1 quart of ATF+4 transmission fluid to drain when the sensor is removed.
4. 4

   Remove sensor mounting bolt
   Using the appropriate socket, remove the single bolt securing the output speed sensor to the transmission case. Keep the bolt in a safe location for reinstallation or replacement.
5. 5

   Extract the old sensor
   Carefully pull the output speed sensor straight out from the transmission case. It may require slight twisting or rocking motion to break it free. Allow transmission fluid to drain completely into the pan. Remove and discard the old O-ring from the sensor bore if it remained in the transmission case.
6. 6

   Clean the sensor mounting area
   Using a shop rag and wire brush if needed, clean the sensor mounting bore in the transmission case. Remove any debris, old O-ring material, or transmission fluid residue. Ensure the mounting surface is clean and free of damage.
7. 7

   Prepare the new sensor
   Verify the new output speed sensor matches the old unit. Install the new O-ring onto the sensor body if not pre-installed. Lightly lubricate the O-ring with clean ATF+4 transmission fluid to ease installation and prevent damage.
8. 8

   Install the new sensor
   Carefully insert the new output speed sensor straight into the transmission case bore, ensuring the O-ring seats properly. Push firmly until the sensor is fully seated and the mounting hole aligns with the threaded hole in the case.
9. 9

   Install and torque mounting bolt
   Install the sensor mounting bolt and tighten by hand until snug. Using a torque wrench, tighten the bolt to specification. Ensure the sensor is properly seated and does not rotate during tightening.
   Torque spec

   Sensor Bolts15 Nm (11 lb-ft)
10. 10

    Reconnect electrical connector
    Push the electrical connector onto the output speed sensor until it clicks securely into place. Gently tug on the connector to verify it is fully locked.
11. 11

    Refill transmission fluid
    Locate the transmission fluid dipstick near the rear of the engine bay on the driver side. Using a funnel, add approximately 1 to 1.5 quarts of Mopar ATF+4 transmission fluid through the dipstick tube to replace what was lost during sensor removal. Do not overfill.
12. 12

    Check fluid level
    With the engine running and transmission in Park, allow the transmission to reach operating temperature (approximately 180-200°F). Check the fluid level on the dipstick with the engine running. The level should be in the HOT range. Add fluid as needed in small increments.

Reassembly

1. Reinstall driver side front wheel if removed, torquing lug nuts to factory specification
2. Lower vehicle from jack stands
3. Remove wheel chocks
4. Dispose of used transmission fluid at an appropriate recycling facility

Verification

• Start the engine and verify no transmission fluid leaks around the output speed sensor
• Using a scan tool, verify the output speed sensor is providing a signal and no diagnostic trouble codes are present
• Test drive the vehicle and confirm the transmission shifts properly through all gears
• Monitor speedometer operation to ensure it functions correctly
• Recheck transmission fluid level after test drive and top off if necessary

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