Neutral Safety Switch

Remove and replace the neutral safety switch on the transmission of a 2005 Dodge Viper with 8.3L V10 engine, which prevents starting unless in Park or Neutral.

Warnings

Tools required

Parts

• Neutral safety switch × 1 — Use OEM specification
• Transmission fluid (if spillage occurs) × 1 — 75W-90 synthetic GL-4

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 starter activation during procedure
4. Raise front of vehicle using floor jack and support securely on jack stands at proper lift points
5. Allow transmission to cool if vehicle was recently operated

Procedure

1. 1

   Access transmission from underneath
   Position yourself under the vehicle with adequate lighting. The clutch pedal position (start interlock) switch is located at the top of the clutch pedal assembly inside the cabin; if instead servicing the transmission-mounted backup lamp switch, it is located on the transmission case. Identify the switch body and its electrical connector.
2. 2

   Disconnect electrical connector
   Locate the electrical connector attached to the neutral safety switch. Press the locking tab on the connector and pull it straight off the switch terminals. Inspect the connector pins for corrosion or damage. If corrosion is present, clean with electrical contact cleaner.
3. 3

   Clean switch mounting area
   Clean any dirt, debris, or old fluid residue from around the switch area with a shop rag. Avoid wire brushing near an open transmission port to prevent contamination from entering the transmission.
4. 4

   Position catch pan
   Place a catch pan directly beneath the neutral safety switch. When the switch is removed, some transmission fluid will drain from the opening. Have shop rags ready to control spillage.
5. 5

   Remove switch mounting bolts
   Remove the case-mounted switch — verify whether it is a threaded screw-in switch or a bolt-retained switch per the FSM before proceeding (unbolt or unscrew as appropriate). Keep these bolts if they are in good condition, as they may be reused. Once bolts are removed, carefully pull the switch straight out of the transmission case. Note: Unverified — confirm switch retention method (threaded screw-in vs bolted) and fastener size in the 2005 Viper FSM.
   Torque spec

   Switch Mounting Bolts15 Nm (11 lb-ft)
6. 6

   Inspect transmission case opening
   With the switch removed, inspect the transmission case opening and the internal shift mechanism visible through the opening. Look for metal debris, damaged sealing surfaces, or worn components. Wipe the sealing surface clean with a shop rag.
7. 7

   Verify shifter position alignment
   Before installing the new switch, verify the transmission is in Neutral. On this manual transmission the start-interlock function is provided by the clutch pedal position switch; if servicing the case-mounted backup lamp switch, confirm shifter neutral alignment. This ensures proper switch operation.
8. 8

   Install new neutral safety switch
   Install the new neutral safety switch into the transmission case opening, ensuring the internal actuator engages properly with the shift mechanism. Align the switch mounting holes with the case. Push the switch firmly into position to seat it against the transmission case.
9. 9

   Install and torque mounting bolts
   Install the 2 mounting bolts by hand to start the threads. Once both bolts are started, torque them in a crossing pattern to the specified torque using a torque wrench. Do not overtighten, as this can crack the switch housing.
   Torque spec

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

    Connect electrical connector
    Push the electrical connector firmly onto the switch terminals until the locking tab clicks into place. Tug gently on the connector to verify it is fully seated and locked.
11. 11

    Check transmission fluid level
    If significant fluid was lost during switch removal, check and top off the transmission fluid level according to manufacturer specifications. The T-56 manual transmission uses the factory-specified ATF-type manual transmission fluid (verify exact spec in FSM). Add fluid only if necessary through the fill plug opening.
12. 12

    Reconnect battery and lower vehicle
    Reconnect the negative battery cable. Remove jack stands and carefully lower the vehicle to the ground. Remove wheel chocks.

Reassembly

1. Ensure all electrical connections are fully seated and locked
2. Verify no tools or parts were left under the vehicle
3. Wipe up any spilled transmission fluid from under the vehicle

Verification

• With brake pedal depressed, verify engine starts only in Park and Neutral positions
• Attempt to start engine in Drive and Reverse positions - starter should not engage
• Verify reverse lights illuminate when shifter is moved to Reverse position
• Check for transmission fluid leaks around the switch after test starting
• Test drive vehicle to confirm normal operation and proper shift indicator function on instrument cluster

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle