Neutral Safety Switch

This procedure covers replacement of the neutral safety switch on the 47RE or 48RE automatic transmission, which prevents starting the engine in gear and controls reverse light operation.

Warnings

Tools required

Parts

• Neutral safety switch × 1 — Mopar 4799056 or equivalent
• Switch mounting bolt O-rings × 2 — Usually included with switch
• Transmission fluid × 2 — Mopar ATF+4

Fluids

• Mopar ATF+4 — 2 qt

Preparation

1. Park vehicle on level surface and apply parking brake firmly
2. Place wheel chocks behind rear wheels
3. Disconnect negative battery cable to prevent accidental starting
4. Raise front of vehicle with floor jack and support on jack stands at frame rails
5. Allow transmission to cool if vehicle was recently operated

Procedure

1. 1

   Locate neutral safety switch
   Position yourself under the driver's side of the transmission. The neutral safety switch is located on the driver's side of the transmission case near the shift lever/linkage. It is a switch with an electrical connector; confirm its exact mounting style (threaded-in switch versus bolted retainer) against the factory service manual for your specific transmission before removal.
2. 2

   Disconnect electrical connector
   Press the release tab on the electrical connector and pull it straight off the neutral safety switch. Move the connector and wiring harness out of the work area. Inspect the connector terminals for corrosion or damage.
3. 3

   Position fluid catch pan
   Place a fluid catch pan beneath the neutral safety switch location. Only a small amount of transmission fluid (typically a few ounces) may weep from the switch bore during removal; verify the switch location relative to fluid level in the factory service manual.
4. 4

   Remove switch mounting bolts
   Unscrew the neutral safety switch from the transmission case using the appropriate wrench or socket on the switch body (or remove the retaining hardware if a bolted design). Be prepared for a small amount of fluid flow as the switch is removed.
   Torque spec

   Switch Mounting Bolts15 Nm (11 lb-ft)
5. 5

   Remove old switch
   Carefully pull the neutral safety switch straight out of the transmission case. Fluid will drain from the opening. Allow fluid to drain completely into the catch pan. Remove and discard the old sealing O-ring or washer from the switch body.
6. 6

   Clean mounting surface
   Use a wire brush and brake cleaner to thoroughly clean the mounting surface on the transmission case. Remove all old gasket material, debris, and fluid residue. The surface must be clean and dry for proper seal. Do not allow debris to enter the transmission opening.
7. 7

   Prepare new switch
   Install new O-ring seals onto the new neutral safety switch or into the mounting bolt holes, depending on design. Lightly lubricate the O-rings with clean ATF+4 to aid installation and prevent pinching. Verify the switch rotor is aligned properly with the detent in the transmission case.
8. 8

   Install new switch
   Carefully align the neutral safety switch with the mounting holes and the internal rotor detent. Push the switch straight into the transmission case until it seats fully against the mounting surface. The switch should sit flush with no gaps.
9. 9

   Install and torque mounting bolts
   Thread the neutral safety switch in by hand to avoid cross-threading, then torque the switch to the factory specification (approximately 24-25 ft-lbs for a threaded park-neutral switch — verify against the service manual) using a torque wrench. Verify no fluid leaks around the switch after tightening.
   Torque spec

   Switch Mounting Bolts15 Nm (11 lb-ft)
10. 10

    Reconnect electrical connector
    Push the electrical connector firmly onto the neutral safety switch until you hear or feel a positive click. Gently tug on the connector to verify it is locked in place. Route the wiring harness away from hot exhaust components.
11. 11

    Refill transmission fluid
    Add Mopar ATF+4 through the transmission dipstick tube only as needed to replace the small amount of fluid lost during switch replacement (typically a few ounces or none). Use a fluid transfer pump or funnel with long flexible spout. Do not overfill at this stage; final level will be checked with engine running.
12. 12

    Lower vehicle and check fluid level
    Lower vehicle from jack stands. Reconnect negative battery cable. Start engine and allow to warm to operating temperature. With engine idling and parking brake applied, move shifter through all gear positions, pausing 2-3 seconds in each. Return to Park. With engine still running, check transmission fluid level on dipstick and add fluid as needed to reach proper level in HOT range.

Reassembly

1. Verify all tools and parts have been removed from under vehicle
2. Dispose of used transmission fluid according to local environmental regulations
3. Clean up any spilled fluid from undercarriage and ground surface

Verification

• Verify engine will only start in Park and Neutral positions
• Verify engine will NOT start in Reverse, Drive, or any other gear position
• Check that reverse lights illuminate when shifter is moved to Reverse
• Test drive vehicle to confirm proper transmission operation and no warning lights
• Recheck transmission fluid level after test drive with engine at operating temperature
• Inspect under vehicle for any fluid leaks at switch location after test drive

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