Activating my rear locker and/or A Trac when not in Factory Low Range

So, I have a Marlin TacoBox. I have three low range choices: Factory only, Marlin only, and Factory plus Marlin. Factory low is around 2.7:1 reduction. Marlin is 4.7:1 reduction. I find Marlin low to be most useful. Problem: I have no access to my rear diff locker or A Trac when factory low is not being used.

I am hoping someone on here can give me a clue about how I might tackle this issue.

 

Folks are working on a solution, but nothing yet.

Search out @lapoltba 's and @BigWhiteTRD 's threads.

 

Thanks

 

You're welcome!


Enjoy that marlin crawler.

 

I think the thread below has a good bit of the data you need, but its going to need some effort to repurpose it to your particulars...

4WD ECU Spoofer for FJ Transfer Case Install | Tacoma World

The above thread I helped a guy get his rear locker, etc back after a FJ transmission swap, so for that specific swap he no longer had a transmission actuator nor ADD, so schematics are specific to that condition. I assume you are going to be a bit different.

Alot depends on how you envisioning this working
I suggest you take a quick read thru that thread, then come back to this thread and lets discuss what exactly you are shooting for. Think hard of what modes you want what goodies to be functional, as that is going to define how we spoof...

(are you still using factory front diff ADD?)
(do you want to use atrac while the transfer case is still in 2hi, or 4hi, etc....?)

NOTE: any solution that I give you will be an electromechanical solution (relays, switches), not a microprocessor solution. Our ECUs are very sophisticated in monitoring for faults and fail-safes. Some of the work arounds i have found for an electromechanical solution require you to turn truck off to active/deactivate them, so truck ECU doesn't realize what we are doing. Its just the drawback because I can't do a reliable microprocessor solution)

 

Ever thought about getting a CAN sniffer?

 

It's too close to Friday for that.

 

https://www.tacomaworld.com/threads/rear-diff-lock-anytime-mod-3rd-gen-development.537810/

A solution for the anytime locker was developed in this thread

 

absolutely, as in 'it would be interesting if I could'

In terms of my personal skill-set, it would WAYYYY too many man-hours before I felt I could make something like that semi-reliable. Too many other hobbies that I am neglecting as it is.

 

I have considered it, and even bought a spare 4x4 ecu to disassemble and mess with. I just haven't had a chance. I was thinking it may be possible to do a man in the middle type "attack" jus the way (I assume) the speedo recalibration modules work.