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Thread: Transmission control for 4 Wheel Drive low range?

  1. #1

    Default Transmission control for 4 Wheel Drive low range?

    Just purchased the Holley Terminator X Max 550-917 24x/1x EFI System With Transmission Control for Christmas, to go into my '89 Jeep Wrangler swap project. While looking through the instructions and researching online, I haven't seen anything with regards to being able to change the 4L60E shift schedule between 2 wheel drive high range, and 4 wheel drive low range. Is that possible with this system?

  2. #2


    What's the transfer case looking for to change from 2 wheel drive to 4 wheel drive? You may be able to use one of the outputs for the transfer case. Or just do something outside of the ECU (this is what I'd do). Andrew
    IG @projectgattago

  3. #3


    The transfer case is manually shifted. I could use one of my inputs as transfer case HI/LOW. But I'm unfamiliar with the Terminator software in so much as if there is an option to create two different shift strategies depending on the transfer case input. Was just wondering if anyone has tried that yet, or if it's an option.

  4. #4


    I had to use an Advance Adapters part (50-0405) to go between my 4L60E and old NP241 transfer case. I needed it to get everything to bolt together anyway, but it comes with a tone ring and VSS that goes on the output shaft of the transmission. I use this VSS instead of the one in the transfer case. This way, the speed the ECU sees is always the same regardless of transfer case position, so you can ignore the transfer case ratio and you don't need a second shifting strategy. It solves the shifting problem, but your speedometer will be off from real speed, but who needs a speedometer in 4 Low anyway.

  5. #5


    I currently just completed my LS swap into my ZJ using a 4L80E and NP 241. I spliced the 241 VSS into the Holley harness so it shows MPH no matter the range.

  6. #6


    From what I understand, when doing it this way, the VSS would be off in 4 Low, and not sure how the transmission would shift. Have you driven yours in 4 Low? It was my understanding that you would need to install a VSS on the output of the transmission (before transfer case) in order to get it to work correctly (like ninety3) did.

    If it's possible to create a different shift strategy in the transmission based on an input from the transfer case, it would eliminate the need for the extra sensor.

  7. #7


    Agreed, a second shift table would be ideal. No way to do it now though. Stock TCMs have the 4 Low input which is just a speed multiplier, plus two shift tables that you can switch between on the fly. On the Dominator at least, not sure about the Terminator X. You can use a key switch to change tunes, but the ECU has to be off to do it, so that wouldnt work for this. Would be nice if Holley added that to the transmission controls, and also TCC engagement MPH per gear table, like OEM. Or at least more things in the Advanced ICF section.

  8. #8


    My '96 Jeep VSS was located on the output of the 231 transfer case. It always felt like the shift pattern was based on speed in 4 Low.

    What kind of trails are you on that you need shifting in 4 Low. Mostly rock obstacles in Utah so not a lot of shifting gears.

  9. #9


    Understood. Like I said, I have not got it all installed yet, was just trying to figure out what the options are. I doubt I'll be shifting much in 4 Low, but if needed, would rather install the parts now, vs tearing it all apart again later. May just go with the post transfer case VSS for now and see how it acts. Thanks for all of the input!

  10. #10


    We were talking about this the other day on my buddy's Jeep. Even if you have a VSS on the transmission output instead of the transfer case this will work below.

    It will burn 3 Inputs, but you could do the "Paddle Shifters". Look under Transmission tab and Inputs/Outputs tab.

    Even with the LS1B PCM tuning the 4 Low shifts for off-road was a pain. Never seemed to have it just right.

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