PCM of NC 4l60/70 to 4l80 Swap Harness

(2 customer reviews)


    • $
    • $
    • 59.95 $


4L80 Swap Harness:  New, more compact design!  This harness makes a 4L80 swap much simpler.   It is plug & play and requires only basic tuning. (NO SEGMENT SWAP NECESSARY!) Just remove a few codes, re-tune the shift points for the new 4L80e gear ratios and you’re on your way! No complicated OS swaps or hurdles to jump.   Two version of this harness are available:

P-120021 – For 1997-2008 LS-based vehicles with external PRNDL switch (pictured)
P-120022 – For 2009+ LS-based vehicles with internal switch (Must add external switch to your 4L80E) The conversion harness will have an additional connector to plug in the PRNDL switch (not pictured)

This is the easiest solution on the market. Input speed is not used, no input speed sensor wiring is necessary. Only output speed is necessary, using your OEM wiring. PRNDL switch transfers over from your original transmission. For 2009+ models, you will need to buy a PRNDL switch, available for purchase with our harness.   Cruise control and gear shift indicators work just as they did in stock form!

Converts any factory equipped 4L60e, 4L65e, 4L70e & 4L75e to 4L80e in LS-based cars and trucks (not for use in 5.7L Vortec trucks)

Please allow 2-3 days processing time, as these harnesses are typically made-to-order.

Tested in Travis Wester’s GTO to a record 8.74 @ 156.71mph in the quarter mile!

Base transmission startup tunes available for $100 + Shipping.

Featured by GM High Tech HERE!

Download instructions HERE!

Additional information

Weight 1 lbs

2 reviews for PCM of NC 4l60/70 to 4l80 Swap Harness

  1. Travis Wester

    This harness works exactly as advertised. Previously, I controlled my 4l80e with a TCI controller. My cruise control and dash indicators never worked. After I removed the TCI controller and installed this harness everything is functioning just like stock with the stock tcm.

  2. GM High Tech

    The PCM of NC harness works so well, and doesn’t require a segment swap in the computer, that we recommend using it no matter what. For just over 250 bucks, this is the easiest and most complete solution to your conversion tuning woes.


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