Is a Pin-7 Mod (e.g., LC Speak) available to turn CDL off while in 4LO?

Please excuse my LC speak about a

$7 Pin-7 DaierTek Door Pin Switch Car Hood Jamb Auto Alarm Security Adjustable Momentary ON Off 12VDC 20A for Automotive Trunk - 3Pcs

Pin-7 mod. I haven't found an equivalent for a 2000 AC 2UZ with the stock dash switch for 4LO.

I like running the 4LO gear ratio in the mountains. It keeps me from riding the brakes and allows the engine and transmission to run at cooler temps while in the San Juan mountains of Colorado.

On my 99 model LX470 I made the pin-7 mod so CDL would not engage while in 4LO. I understand this is a popular 80 series mod also.

Is there a way to engage 4LO without causing CDL to switch on? I wouldn't mind adding a CDL kill switch if I could control it independent of the 4LO switch.

 

No, it's not just a switch that does this. You're looking at swapping a whole multi-mode transfer case from a 3rd Gen 4-Runner/01-04 Sequoia that has a center differential. Your Tundra doesn't have a center differential, it just uses a locking transfer case.

Unlocked transfer case is 2WD, locked transfer case is 4WD. (Tundra only does this)
Unlocked center differential with 4WD on is AWD, locked center differential and locked transfer case is is true 4WD. (your LX, 3rd Gen 4Rs, and Sequoias do this)

Maybe you could try a switch to the front differential actuator where the front driveshaft spins in 4-LO, but the axles shouldn't send any power.

 

So are you trying to have 2Lo or AWD? I'm confused.

 

4Lo in an AWD/4WD WITHOUT being locked into equal power distribution to the front and rear axles.

4Lo is a good ratio from what I'm experiencing; it's the equal power to front and rear diffs that causes binding that I would rather not have.

 

He's trying to take advantage of lower gearing in the transfer case with 4-LO on pavement. The mod he is suggesting would make it where his truck can run in 4-LO AWD on pavement, but our trucks do not work that way.

The LX470 automatically locks the center differential to turn it into true 4WD whenever you select low range in the transfer case (4-LO button). You can't make it AWD in 4-LO without the wiring modification. The modification he is suggesting overrides this where the center differential remains unlocked while you are in 4-LO, and your truck stays AWD. With the center differential unlocked, the power distribution of front versus rear wheels is always variable, which is why you can run AWD in the pavement. 4WD power distribution in our transfer cases is always 1:1 and does not vary, that is why the drivetrain binds in 4WD on dry pavement.

To turn the LX470 into 2-LO, he would have to do a front ADD discconect switch like I suggested for the Tundra. This way the transfer case engages in 4WD, but the ADD is not engaged. With an ADD disconnect switch, your transfer case still sends power to the front differential, but only the intermediate shaft No.1 on the passenger side will be spinning. 2-LO would be advantageous when backing up a trailer or doing other things on pavement in low gear to avoid binding.

 

An ADD disconnect switch sounds like something I would be interested in learning more about.

Note that I would like to add an Eaton eLocker to the front.

The option would be 2WD & 4WD) 4LO no ADD + Eaton eLocker on demand in 4WD or 4LO (for the lower gear ratio).

 

I've only heard of people doing them when going to manual transfer cases like the Sequoia/4Runner ones. Some people go to the manual transfer cases in these trucks when their transfer case actuator goes out, then use a disconnect switch to engage the ADD.

If you add the Eaton E-locker, definitely keep it disengaged on the pavement. Only time it would be fine to run locked would be in full 2WD but I'd think that would make your steering much more difficult. I wouldn't run 4WD front locked on pavement regardless of 4WD or AWD. But theoretically if you have the E-locker engaged and ADD disengaged, your truck technically becomes 3WD.

To trick the transfer case, you might be able to run a switch off the solid blue wire on the transfer case. When the switch is on, the 4WD system will work normally, and when the switch is off, it disconnects the wire, making the 4wd system think it is in 2wd. There may be an order you have to turn the switches on when you're switching from 2WD to 4-HI then 4-LO, I'd have to read the EWD more to figure out that order.

There is a company that sells an ADD disconnect harness for transfer case swaps, but I'm struggling to find it right now. Can't remember if it tied into this blue wire, or into the wiring on the front diff actuator.



I too am interested in accomplish the same thing you are for mountain driving, except I want the addition of the manual transfer case stick, AWD and neutral gear in the transfer case. With a manual transfer case with a neutral gear, you can flat tow our trucks with the engine shut off.

 

This is some great information, and I appreciate the time you have put into sharing it. I've settled for a 3WD configuration with the front locked. That would meet my needs today. Someday, I may decide to add a rear Eaton eLocker, but that would be a year or two away.

 

I settled with just a rear Eaton e-locker and 4.88s, but sometimes wish I went with a front as well. Even though my goal is a different transfer case, I think I might run a switch like I'm suggesting for you to get 2-LO in the meantime.

I'd get the wiring diagram for your year here and look at page 172 through 175 to get started on a disconnect switch. https://www.tundras.com/threads/ultimate-tundra-wiring-diagrams-collection.81448/

 

Thanks again! I will share whatever I find of value.

For history, I installed a Harrop(Eaton) Front eLocker on the 100 to beef up the stock 2-pinion front to be 4-pinion. Then I have a built rear diff with a Harrop eLocker ready to install. That is going into an 02 model with ATRAC. I've learned the early ATRAC system works fine as long as you stay on camber. If you get off-camber, it seems to stop working or it forgets its purpose. So this LC build will be ATRAC + Triple Locked.

My tough off-road situations are usually off-camber (left or right lean) + on a steep incline with some wet red clay.

I like the Eaton (Front/Rear) systems being on two independent electrical systems to be a fault tolerant type of configuration.

The Tundra has been a surprise with the same power as the 100 yet is is 1,000 pounds lighter. I usually go off-roading two times a week and lead a monthly trail ride of 10 to 20 trucks through the Ouachita Mountains.

So I don't want to be caught without a reasonably capable 4x4 truck.

 

Monthly Quachita trail rides? Why is this the first we’re hearing of this!