GM T56 ’98-02 3-in-One Harness/Reverse Lock Out/


3 in1 T56 harness,
Speedometer output,
reverse lockout, and reverse lights
with solenoid and sensor connectors



Tremec  Magnum 3-in-One Harness w/ Reverse Lock Out


This 3-in-One harness solution is the perfect finishing touch for any Tremec 6-speed Magnum conversion.


MD-700-0102: For   Borg Warner GM Non-Magnum 6-speed.  –  Has Borg-Warner GM VSS connector

Works with Bluetooth smartphone App.

  (  will not work for Ford or Viper  )

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why do you need this?


More on these harnesses.


The 3-in-One harness solution for the Tremec 6-speed Magnum transmission comes equipped with all the connections pre-wired into one harness for a simple installation and ease of use. The small epoxy-sealed controller is mounted to the VSS output using the existing bolt. Once the unit is powered up you will be able to connect via Bluetooth to your Apple or Android smartphone using the free app.
The app will give you the ability to customize the input and output settings for each feature to ensure proper operation in your vehicle.

The 3-in-One harness eliminates the need for any additional equipment to operate the reverse lockout or generate the correct speedometer signals coming from your Tremec 6-speed Magnum.
This 3-in-One harness solution is the perfect finishing touch for any Tremec 6-speed Magnum conversion, and the only harness you will ever need.
Prior to the development of the 3-in-One harness, you would need up to 5 separate parts to perform all the same functions wrapped up in this one harness solution.
Getting the correct speed sensor output and operating the reverse lockout is typically the most frustrating and confusing. The more technology incorporated into hot rods these days sometimes requires specific input signals to allow everything to function correctly.

There may be scenarios where you are using a speedometer that requires one signal and an ECM that requires a completely different signal.  With the 2 speed outputs that are available in the 3-in-One harness, you can independently control the output of each one further eliminating any need for additional equipment and connections. The reverse lockout on the Tremec 6-speed Magnum is another commonly misunderstood feature. The reverse lockout is a solenoid-controlled pin, that uses a spring to exert pressure against the shift rail, to help prevent an accidental shift into reverse when going into 5th gear. It doesn’t prohibit reverse engagement, it only makes it difficult to shift into reverse when it is not getting a power signal. Once power is applied, the solenoid pulls the pin back allowing reverse engagement with minimal effort.
The OE controls this feature using a speed setting to dictate when the pin is pulled rather than a momentary on/off signal.

We’ve incorporated that same speed setting feature into the 3-in-One harness to give you better control over when the lockout is triggered. The Tremec 6-speed Magnum 3-in-One Harness utilizes a small, built-in, epoxy-sealed box that will control each of the 3 functions with power and grounding for each function through a switched +12v circuit and a wire connected to the negative battery post or engine block. Control of the reverse lockout solenoid is based on a user-defined speed setting (Default is set at locked above 4 MPH and unlocked at 0-3 MPH) This eliminates the need for a separate lockout control box which is currently the only option to activate the reverse lockout correctly. For your electronic speedometer, the harness is equipped with 2-speed sensor outputs; the speed sensor outputs generate a square wave signal that goes from about -5 to roughly +5 volts, varying in frequency as the speed changes. But, you say, my ECM input needs a positive only signal. No problem! The output will automatically shift and give you 0 to +10 volts. The 2-speed sensor outputs are completely independent and can be calibrated separately with any pulse count and ratio you want.  So, these two outputs should pretty much be able to drive any common speedometer, cruise control, or ECM.
This will give you much greater flexibility in the components you are able to use and requires less time wiring everything up.

The reverse lights are powered by a single output wire connected to the positive side of your reverse lights; the grounding of those lights should be local to the bulb socket.

There is no easier solution for setting up your Tremec 6-speed Magnum transmission!
Tremec 6-speed Magnum Reverse Lock Out Module Vehicle Speed Sensor with Dual Output, pre-set as GM 40 pulse output on one and 16 pulse output on the other.
This function can be adjusted with your iOS or Android device.  Includes wiring for reverse lights, reverse lock-out, and vehicle speed sensor.

Additional information

Weight 16 oz
Dimensions 1 × 1 × 1 in




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