How-to guide for converting your 2007-2013 Tundra to Full Time AWD capability

Any preliminary thoughts on how it drives/feels?

 

2wd was normal as well as in 4hi unlocked(awd). I didnt get on it and just drove in the rain yesterday running to a few stores. Pulling out into traffic or taking off from a slight incline I'd always spin the wheels. Not anymore! Why did I ever wait so long to do this!
As been said before the Tundra should have come with awd option and a rear locker/lsd.

 

I'm in a unique position as I own the bookends of the 2nd Gen tundra. I inherited my dad's 2007 4wd extended cab limited and also have a 2021 4wd platinum crewmax. Since the 2021 is supercharged (2650 stock pulley and tune, for now...)and have a powertrax, the power is useless if the roads are wet: instant sideways.

From my understanding the 4wd computer is behind the glovebox on both trucks. Seems like i need or order a 2021 Sequoia 4wd computer and start looking at the difference in wiring on the two trucks. Does that sound logical? Obviously my 2021 has the borg warner TC and computer, i'm just hoping the wiring is similar, but the unknown is if the aisin computer plays nice with the 2021 can bus system, is this correct?

I don't care about having the cluster from a sequoia as I'll just put in a switch that i'll have the illumination tied to the computer to be on when the center diff is locked.

 

I know when @ViktorG looked into it the wiring is completely different and may be done if you figure it out the wiring. The switch is a momentary one Not off/on for sequoia. Not sure for the borg warner. You're pretty much on your own as you'll be the first to attempt it.

 

Does it sound logical to get a 2021 sequoia 4wd computer for research? I would need to get the EWD for both 2007 and 2021 for both via the TID site? I assume I need to build a harness from the 4wd computer to the transfercase and maybe just harvest the ECU connections. I'm not really sure what I'm talking about just want to get my the first steps thought out.

So I would be better to source the sequoia switch, where is the sequoia switch anyway? a picture is worth a thousand words, i assume it's much like the center diff lock i had on my 100 series land cruiser, may she rest in peace.

 

The land cruiser I believed used a on/off switch. I used a $10 lighted momentary switch from Amazon.
You will have to study the wiring. What controls the ADD, 4l, 4hi etc. I would get the wiring diagrams for each and study those. Seeing where one could use the existing wiring. And fab up your own? or get the wiring harness from a Sequoia and see what can be done.
Just lots of research on controller/relays and how they differ.

 

I think you are right, it was an on off switch and the diff lock light would flash similar to how 4HI flashes when shifting and then stay lit when locked. So you think complete wiring harness from a sequoia that goes from the TC to computer? That would be easier that building my own harness, but might not be as fun. Yeah I have one of those cheap round Amazon switches that lights up mounted inconspicuously that cuts power to my v1 i have mounted up above my rear view mirror. I can get the exact same one in different color in momentary config for the center diff lock. If i can figure things out I'll post of my results in a new thread i suppose.

 

I liked the cruiser switch and bought one but @Wynnded reminded me it's a momentary switch.
I would compare the 2nd Gen Tundra wiring to the Borg Warner and see what is similar and what controls are different. Then it's a easy. The only difference between the Tundra and sequoia is the 4wd ecu and adding pin 12 grounded for 4wd plus slicing into pin 14 for diff lock switch. Download both wiring diagrams and start mapping them out.

 

The 2.5 Gen receives a very different looking Borg Warner ECU. The big questions, can the existing tundra harness have the connectors swapped and re-pinned? If yes, will the Canbus in the Tundra talk to Sequoia ECU?

Borg Warner ECU


Sequoia ECU (part 89533-0C060 should be for 21, but verification needed)

 

This!! Gotta talk to each other. Only way to find out is try...

 

That was my question as well, I'm confident I can reuse the harness, or make a new one. I'm most concerned that the logic to talk to the Aisin 4WD computer is there in the 2021 tundra ecu. I aim to try that is for certain. How many miles is acceptable on a used sequoia transfer case?

 

89533-0C060 looks to be the part number for a 2021 Sequoia 4WD control computer, it's actually cheaper than the 89533-00032 one.

 

The JF Series Transfer Case is very stout, nicely built, and well lubricated (all the important parts are pressure fed via oil pump). Even with minimal maintenance, they go hundreds of thousands w/o issue. Still, buy the cleanest/lowest mileage that fits your budget.

 

One from a snow filled rust belt will be used more than from more warmer climate areas. I got mine from sw WA with 81k for $500. But I was looking for a while.

 

So brain storming here, how can I test out the part number 89533-0C060 2021 Sequoia 4WD computer before I completely hack up my wiring harness? I assume I can get any harness from a 2007-2013 tundra or 2nd gen Sequoia and run it and fashion up some jumpers at a minimum to use it to plug into the Sequoia transfer case I source prior to install and see if it shifts it and does not freak out the 2021 tundra ECU? Also how do I identify and order the different connectors that toyota uses? I feel completely comfortable soldering and heat shrinking the harness, I once did that to my supercharged third gen 4runner's ECU harness, ran some of Gadgets tuning goodies, lol) I really just don't want to do the whole thing to discover it's not going to work. Thoughts?

 

Any direction/input @Mdl or @Jowett for my crazy attempt at the never done before?

 

Do you have the wiring schematics of both tundra years to compare and see where they differ on signals for engage/disengage etc?
That's the biggest hurdle is finding out how the aisin and borg unit differ on types of signals used and while keeping the main ecu happy.

 

Start here, http://zatonevkredit.ru/schemes/path/80a2354fa0510d9ecf99
they have a good helping of wiring diagrams. Nothing past 18 or 19 model year, but it will allow you to get an idea of the various systems and their differences between the two vehicles. I did take a quick peek, and both vehicle have a CANH and CANL terminals on the 4WD ECU.

 

Yes sir I have the EWD for 2007 tundra, 2021 Sequoia and 2021 tundra 4WD computer and solenoid connections. My main concern is if I go ahead and source the 2021 4WD computer and wiring harness that It does not freak out the can-bus system. It has the same connections to it (wiring, not connectors) but does 2021 tundra ECU speak Asian? I assume that beyond the 4WD (asian/borg warner) ecu output to can-bus would be identical, but you know where assuming gets you. I just would like to test that before I swap in the transfer case to find out that it will not work.

 

I have the same thing from TIS, I noticed the same thing, CANH and CANL is on both the Aisin and the Borg Warner. I'm not a wiring expert, but i administer networks and firewalls and assume can bus is a network and there are standards.

 

There’s a very good chance that the Sequoia 4WD ECU will signal through those two connections and say what your Tundra want’s to hear, but we are way outside my wheelhouse here. With that said, it’s still a big ?? we can’t answer.

 

So the easiest path forward for me would be to source the following:

1. 2021 Sequoia 4WD ecu
2. transfer case to 4WD ecu wiring harness from a 2007-2013 tundra or 2nd gen Sequoia
3. transfer case from 2019 sequoia i have an eye on with 60k miles

Wire up 2021 Sequoia 4WD ecu temporarily in my 2021 tundra and attach to uninstalled transfer case. Power the vehicle and switch on 4WD and verify transfercase shifts and 4HI lights on dash, press diff lock and check behavior, switch to 4LO and verify shifting.

If this all checks out, proceed to install transfer case and shorten rear drive shaft and permanently install and have fun!

This sound logical?

 

That should do it.

 

Okay this will be my winter project, I'd like to get this done before I take my family skiing in colorado, but I know that is not likely.

 

Yes...

 

89533-0C060 (2021 4WD Sequoia ECU) ordered, there is a 2012 Sequoia transfer case close to me, no differences in mechanical between all the years, just electronics?

 

There’s a split in the shift actuator part number in 2010, it may be inconsequential, but I would buy something 2011 or newer.

 

Just got my TC, gonna join the club when I have time to install. Anyone have any tips for installing or wiring, I'll be doing the swap in the street in front of my house..

 

Started my Sequoia transfer case swap last week,

Wisconsin winters suck, also do the swap before you apply Woolwax/Fluid Film.

It has so far sucked,

Couldn't get the cross member off and I left the Isolation bracket attached to the crossmember(completely seized up)
I was able to get the transfer case out with the help of a transmission jack(by myself)
(I had to have help installing the Sequoia one, didn't use the jack had to wiggle it around to get past the crossmember)

Stripped out 3 of the bolts to the Transmission.
Tried soaking them with penetrating oil from the back side, heat from a bolt buster, nada they stripped out.
I drilled one out and ran a bolt thru with a nut on the back side, the others I re-tapped and used Red loctite.
The Recut threads were a little loose but not bad.
After I reinstalled the transfer case the re-tapped ones held up without stripping out, the threads were jacked up near the start of the threads at least.

It was exactly 1.25" longer than the Tundra transfer case.

Driveshaft was taken up to Green Bay to MSI, hopefully I can get it next week.

Once I get the driveshaft installed I can lower it and add the new diff fluid.
I went with Amsoil instead of the liquid gold Toyota stuff.

Now time to do some wiring.

Thanks to @07 Tundra Steve @Mdl @Wynnded

And for figuring this out
@ViktorG

 

@Jowett was one, if not the first one, to figure this out (or at least share it). Worth crediting.