Transmission Range Sensor

Replace the transmission range sensor (neutral safety switch) on the 47RE/48RE automatic transmission to restore proper gear position detection and starting safety function.

Warnings

Tools required

Parts

• Transmission range sensor × 1 — Mopar 4897321AA or equivalent
• Transmission range sensor seal/O-ring × 1 — Often 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 to cool if vehicle was recently driven (fluid can be hot)
4. Raise front of vehicle and secure on jack stands rated for vehicle weight
5. Locate transmission range sensor on driver's side of transmission near transmission pan, attached to valve body

Procedure

1. 1

   Disconnect battery negative terminal
   Disconnect the negative battery cable(s) to prevent accidental starting. Note this diesel uses dual batteries; disconnect the negative terminal on both batteries.
2. 2

   Access transmission range sensor
   From underneath the vehicle, locate the transmission range sensor on the driver's side of the transmission case. It is located on the driver's side of the transmission case near the manual shift lever shaft. On the 47RE/48RE this is typically a threaded neutral safety/park-neutral switch that screws into the case, with an electrical connector on top. Verify the exact mounting style on your unit before removal. Clean the area around the sensor with a wire brush to prevent debris from entering the transmission.
3. 3

   Disconnect sensor electrical connector
   Press the tab on the electrical connector and pull straight out to disconnect from the transmission range sensor. Move the wiring harness out of the work area.
4. 4

   Position drain pan
   Place drain pan directly beneath the transmission range sensor location. Transmission fluid will begin draining immediately when the sensor is removed. Position pan to catch any fluid that drains; expect minimal loss (a few ounces) for a threaded case-mounted switch, though have capacity ready in case the sensor bore is below fluid level.
5. 5

   Remove sensor mounting bolts
   If the switch is a threaded type (typical for 47RE/48RE), use an appropriately sized wrench or switch socket to unscrew it from the transmission case. If your unit instead uses a bolt-on sensor, remove the retaining bolts. Confirm the mounting style before proceeding.
6. 6

   Remove transmission range sensor
   Carefully pull the sensor straight out from the transmission case. Fluid will drain from the opening. Allow fluid to drain completely into the pan. If sensor is stuck, gently pry with a flathead screwdriver while pulling outward. Remove and discard the old O-ring seal from the sensor bore.
7. 7

   Clean sensor mounting surface
   Clean the sensor mounting surface on the transmission case with a shop rag. Remove any old gasket material, debris, or ATF residue. Inspect the bore for damage or debris that could prevent proper seating of the new sensor.
8. 8

   Prepare new sensor
   Install the new O-ring seal onto the new transmission range sensor. Lubricate the O-ring lightly with clean ATF+4 fluid to aid installation and prevent seal damage. Verify the sensor rotor/arm is in the correct position matching the transmission's internal shift shaft.
9. 9

   Install new transmission range sensor
   Align the sensor rotor with the transmission's internal shift shaft. Push the sensor firmly into the transmission case until it seats completely against the mounting surface. The sensor should slide in smoothly without forcing. If resistance is felt, verify rotor alignment with internal shaft.
10. 10

    Install and torque sensor bolts
    If the switch is a threaded type, thread it into the case by hand, then torque the switch to specification (typically about 24 ft-lbs on the 47RE/48RE) using a torque wrench. If your unit uses bolts instead, install and torque them evenly to specification. Do not overtighten as this may damage the switch or case threads.
11. 11

    Reconnect electrical connector
    Reconnect the electrical connector to the transmission range sensor until it clicks into place. Verify the locking tab is fully engaged and the connector is secure.
12. 12

    Refill transmission fluid
    Add approximately 1.5 quarts of Mopar ATF+4 transmission fluid through the dipstick tube to replace fluid lost during sensor replacement (ATF+4 supersedes the earlier ATF+3 used on 1994-1997 models). Use a funnel designed for transmission service. Do not overfill.
13. 13

    Reconnect battery
    Reconnect the negative battery cable. The PCM will need to relearn shift points during normal driving.

Reassembly

1. Lower vehicle from jack stands after verifying all tools and drain pans are removed from under vehicle
2. Remove wheel chocks

Verification

• With engine off and parking brake engaged, verify vehicle will only start in Park and Neutral positions
• Start engine and verify proper gear indicator display on instrument cluster
• Cycle transmission through all gear positions (P-R-N-D-2-1) and verify smooth engagement and correct indicator display
• Check for transmission fluid leaks around sensor location with engine running
• Check transmission fluid level with engine at operating temperature and running in Park on level ground
• Test drive vehicle to verify proper shift points and no check engine light. PCM may take several drive cycles to relearn adaptive shift strategy
• Scan for diagnostic trouble codes after test drive to ensure no transmission-related codes are present

Related trouble codes on this vehicle

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