On occasion, here in Utah, I drive along pretty curvey canyon highways when snow is sticking to them. For the most part traction is fine but can get patchy. A majority of the time its a situation where I would prefer a selectable AWD rather than conventional 4x4 because I have a paranoia about binding and exploding my transfercase.

I like the Multi-Mode option because it is a self-contained unit (no dash switch).

So what I am looking to do here is start a bit of a group-think to help me compile a "parts-n-proceedure" list. From this I hope to be able to make the gofer decision. Many of you are far more technical than I am so your input is very much appreciated.

My main concerns are transmission/transfercase compatibility, 4x4 ECU functions, and anything else electrcal. The mechanicals I think would be pretty straight forward, the biggest issue would be modifying drive shaft lengths.

The floor is now yours...

You would need a limited transfer case, shift case knob, limited front, rear drive shafts and 4x4 ecu.

Swap is pretty straight forward. Mechanically.

Electrically, 3 sensors on the transfer case, electric actuator, one sensor on the front diff, 2 electronic solenoid valves for the ADD, and push button switch on shift knob.

Pretty simple.

Honestly, if you're that worried about traction, you should just put it in 4WD Hi, and go for it. The speeds are almost the same, as long as you're not doing 100MPH.

The Multi-mode case wouldn't help you at all. If the areas are as "patchy" as you say, before the 4WD engages, you'd be out of them.

While Singtoe is right, he did forget one crutial part of the equation.

If your T-case has a Center Locking Diferential, you need the wiring harness from the ECU to the engine, and the transmission.

You CAN NOT just hook up the t-case with a CLD and try to splice the wires. It won't work at all.

Honestly man, Just stick with what you have.

Put it in 4WD, and drive. When you get to the other side, disengage the 4WD.

No biggie at all.

Singtoe,

It took me quite a while but I finally searched into an old news post you made on someone asking the same question that went nowhere. You mentioned the wiring harness in it (which makes sense). Is that its own independent harness or would I have to splice out the connections I needed? You are, after all, the King of Wire Harnesses.

In that same thread RonMaiden talked about associated wheel sensors. Such a thing didn't sound familiar to me.

This would be going into my Tacoma so Im sure I'd just have to have my drive shafts altered accordingly. I would also forego a dash cluster swap and splice in a remote AWD light.

Being that I have an e-locker would the vehicle I source a 4x4 ECU from need to have one as well or are all 4x4 ECU's locker inclusive?

Ok. So you've got a Taco.

Dude, you're probably going to have a hell of a time trying to do it.

Like I said before, you NEED the harness.

Only downfall is, you wouldn't know if it'll plug into your computer.

I know on 96-98 4Runners, the computer connections are completely different than on a '99.

I still stick with what I said earlier. Just engage the 4WD, and then drive.

Doc2012,

I guess what I would want out of this swap would to be able to run in unlocked 4Hi for long durations and have the peace of mind of not binding on the more windy(curvaceous) highways in my area. I have experienced complete lockup and can see it having a devastating effect with more momentum involved. Its not a excessive speed issue that Im trying to resolve. Shifting in and out as needed is an option when conditions keep me under my 30mph shift limit, but in that situation conditions would permit running full-time conventional.

Maybe Im just crazy for trying to Mod for an ocassional situation.

I would be curious to know the communication requirments a center diff would have with Master ECU.

I'm not saying that there's not a reason for you doing this. Please, do not take it that way at all.

Everyone has thier mods, and while some might not agree with what they want to do, it is perfectly fine for them.

Again, I'm in no way trying to discredit you from doing this, just letting you know what it would be easier to stay in 4H than to do this.

While I can not tell you what the CLD has to do with the ECU, I CAN assure you that the CLD is spliced into the Transmission harness from the factory.

When I did my 4WD swap on mine, I found a exact match 4Runner, just a 4WD. Same year, same gear ratio, everything.

The 4WD computer harness is already in the truck, just wasn't hooked up.

Now, when I tried to hook up the 4WD transmission to the 2WD harness, I found that the harness was 1), too short, and 2) didn't have all the plugs needed for the CDL and 4WD.

So, I had to pull out the harness from the 4WD, as well as the ECU, and swap that all over before I could get her to run again.

Now, the harness I had was chopped. How, why, IDK, it just was. What I did, was spliced the wires back together, and it worked.

I tried to get a harness out of a '98, and it was a completely different connector than what was on the '99. There went 200 bones on that one....

If you want to do it, and have it done right, you're probably going to need everything from that other rig. The ECU, wiring harness, the t-case, sensors, everything.

I really don't under stand the "unlocked 4HI" part. I'm guessing you have a e-locker?


If you don't want the E-Locker to engage while you're in 4WD, it'd be a lot easier to add a switch inbetween the e-locker and the sensors, to basically trick the sensor into thinking it was in 2WD. Then, when you needed it, lip the switch and it'll be there when you want it to be.

Then again, you can always get an ARB Air Locker.

No discredit taken. I like to feed off the experience of others and I ask a lot of questions in the process. I actually stumbled across one of your posts yesterday and saw your signature and naturually had to start digging for some sort of build thread THAT YOU DONT HAVE LINKED IN YOUR SIG, wtf. I appreciate your contribution. It all goes into the pile that is what I need to know about this job and I thank you.

The "Unlocked 4Hi" comment refers to running in AWD Mode, Center Diff Unlocked, or Button Only 4x4.

The E-Locker is selectable. I actually need to do the "Grey Wire Mod?" to get more use out of it.

All the Center Locking Differential does is to engage both the front and rear wheels.

There have been people who have the front wheels work, but not the back wheels, and that's because the CLD isn't engaged.

The button that is on the shifter is to engage that CLD.

The CLD has NOTHING to do with the differentials.

From the sounds of it, you have the ADD system in your truck. If I'm correct, the only the only thing that is different between the ADD and manual, besides the hubs and CV, is the passenger side tube. The acutator that is on the passenger side tube is what engages the 4WD. Once you pull the t-case selector, you the actuator slides over, and engages the passenger side drive shaft, making it 4WD.

You CAN make that a manual diff, just by using a hose clamp. Then you can do the Manual hub swap. If you know you're going over those hills, keep the hubs locked, and just engage it in 4WD, then keep going. Stop once you get clear of it, and then unlock the Hubs.

Another thing to watch out for is the CLD not engaging properly. A lot of people report problems with them, from not using them enough and the contacts getting ruined, to other problems. You CAN NOT take that acutator off of the t-case with out taking the t-case apart either. That's a major PITA.

Honestly, I would just stick with what you have. If the "grey wire mod" is what i think it is, basically making the e-locker engage in 4H, I would do that instead. The only time you're really going to notice binding is if you're making a sharp turn, like a u-turn or dough nut. Even then, if there's snow on the ground, you probably won't even notice the binding that much.

The reason my build thread isn't linked in my Sig is because I ran out of room.

And, since you asked for it, here's two of my links. The first is my build thread, and the second is my mod thread. Just some stuff Ive been doing along the way.

Doc's ZRV(Pic Heavy)

Doc's mod thread.

Lot of reading.

The Transfer case ecu is a separate system and does not need to be tied in or to the engine ECU. It does not need to be tied into the e-locker either.

It can be done. You need every thing listed.

Limited front drive shaft
limited rear drive shaft
limited transfer case
limited transfer shift knob (AWD button)
limited transfer case ECU

Wiring goes as the following:

The Transfer case ecu has 26 pins (9 of them not used , 2 of them used for dash indicator)

Pin 1 - Not used
pin 2 - Not used
Pin 3 - Speed sensor - Not need if you engage on the fly.
Pin 4 - Switch on transfer case knob - to engage AWD
Pin 5 - Not Used
Pin 6 - Detection switch on transfer case (center diff lock engaged)
Pin 7 - Detection switch on Transfer case ( Switch that is when shift lever is pulled back to lock Center diff)
Pin 8 - Goes to pin 6 on the actuator motor on the transfer case.
Pin 9 - Goes to pin 4 on the actuator motor on the transfer case.
Pin 10 - Goes to 4wd VSV switch on drivers inner fender.
Pin 11 - Not used
Pin 12 - +12 volts
Pin 13 - Goes to pin 3 on the actuator motor on the transfer case.
Pin 14 - Not Used
Pin 15 - Not used
Pin 16 - Goes to Cruise control ecu - Not needed
Pin 17 - +12 volts from the neutral park safety switch ( wire it with pin 12 to save a step)
Pin 18 - Detection switch on transfer case. (from H2 to H4F)
Pin 19 - goes to front axle ADD indicator switch.
Pin 20 - Goes to center diff lock light in instrument cluster. ( tells driver the center diff is locked)
Pin 21 - Goes to the 4 wheels pictograph in the instrument cluster. (Tells the driver that the 4 wheels are engaged.
Pin 22 - Goes to pin 5 on the actuator motor on the transfer case.
Pin 23 - Goes to 2wd VSV switch on drivers inner fender.
Pin 24 - Not used
Pin 25 - Ground
Pin 26 - Goes to pin 2 on the actuator motor on the transfer case.



Doing the swap is very feasible.

@Singtoe I've been collecting parts for years now but was hesitant to make the swap til i saw this post. I wanted to Thank you. Thank You! This post made everything click together for me. I just finished putting in a multimode VF3AM in my 01 Tacoma.

Very Feasible indeed!

CK

So did anybody have any success with this? Or even attempt it?

I'm attempting it on my 95 SX single cab.

I’ll be attempting this next summer, i bought a 5 speed that needs it. I have a second 3rd gen limited as a daily driver, if you live in Minnesota or anywhere with chitty roads... that AWD mode is worth a million bucks in the winter, awesome traction and can pull into parking lots with no worries


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Singtoe, Great post, thanks for the info.