2 low mod

I've read on another forum about a 2 low mod with add. I was wondering if anyone has done this on here. If so how do you like being able to have two low. Also, have you had any trouble with it. thanks in advance

 

The gray wire mod just allows one to engage the rear locker at any time. It does not allow 2lo.

 

I did what would become known as the "2 lo" and "the gray wire" mod 14.5 years ago on my 2 week old 99 v6 5spd with manual "j-shifter" transfer case. No problems at all.

On road you can creep along much slower in bumper to bumper traffic, not having to constantly be using the clutch.

Off road it comes in real handy on really rough/bumpy sections of trail that do not require 4wd but do require very slow speed. Here it just saves a little wear and tear.

 

I got my 2 low when I did my dual cases and I use it more than I expected to. For me it's usually in bumpy trail that doesn't require 4wd. Also, I use it when I need to carefully park the truck. It's handy.

 

heres the write up on the 2lo mod with a j shifter . I was just wanting to make sure people with it didnt have any thing tear up after doing this. I pull alot of trailers sometimes i have to back them in where there is not much room to turn so it would really help me out on that. thanks for the input

 

It will not hurt a single thing. In fact, to a degree there will be less wear on the side/spider gears and the little needle bearing in the driver side of the diff. Sure the drive shaft and diff carrier will now be spinning but those items could spin nearly for ever unloaded. Thousands of folks have done this over the years with no issues.

When we were discussing allowing 2 lo in the beginning years of TTORA, long before the folks in that link came along, it was not clear how or if any other functions such as ABS or engine control were affected thru the ECM by the easy, quick method of simply fooling the 4wd switch. This was due to the "4 lo" switch being activated when the case is shifted into lo. For that reason (and being in a hurry) I used a switch, DPDT IIRC, to maintain all the circuits to the ADD vsv's in the "ADD off" condition in addition to interrupting the 4wd switch. Yea, it was way overkill.
Either method for the manual cases is really an "ADD disable" switch that by default allows 2wd lo.

One more advantage to this mod is the ability to shift the transfer into 4wd on dry pavement to spin up the front drive shaft. If you do not see regular 4wd action, doing this will help keep the front diff pinion seal and the front transfer case output seal feeling young, along with the surfaces they ride on (rust).

 

I would do that but I have an 85 pickup for as my trail truck. I do light off roading in this truck so I dont need twin sticks for what i do in my 99.

 

Thank you for answering that for me. thats exactly what I was needing to know.

 

Could you explain how you did yours? I was going to follow the write up on ttora but my transmission control relay only had 5 wires going to it and looks nothing like the one on ttora. I have a 2000 5sp 4x4 v6 with add.

 

The extra wires may be for auto trans trucks, I just don't remember.

At the time I actually made a diagram and stuck it in my FSM but it seems to have "taken feet".
The simplest method to defeat the ADD system on a manual transfer case truck is to put a switch in one of the wires going to the 4WD switch, does not really matter which one. I would go with the "red with white stripe". The white with black stripe is a ground that splices into a few other grounds on it's way to the actual ground point. The wire colors and all the info in this post for a 99 but the 2000 should be the same. I'm just not 100% on that.
Switch open, no ADD system operation and no 4wd indicator light.
It should not be a big deal for you to trace said wires back to a convenient area for the splice work. Just make sure you do not go beyond any points where additional wires are spliced together. As I remember the red/white trace wire ends up in a 2 wire, gray, "harness to harness" connector about 2" below the driver side exhaust manifold. If you locate that connector, unplug it and drive around with the transfer in 4wd. If it is the right connector there will be no 4wd light and the front diff will stay disconnected.

In the pic below (by "ShowStop" TTORA)
#1=4wd sw (the one you want)
#2=Transfer Neutral sw
#3=4lo sw

 

Thanks for the reply. I actually took my volt meter and began testing the wires on the transmission control relay. It had transmission relay wrote on it. Under passenger kick panel. I found 4 of the 5 wires had a constant 12 volts and 1 did not. Removed the pin there with a blue/red wire and tested it around the yard and sure enough in 4 lo I had 2 lo. Added a switch there and all is well.

 

You peaked my curiosity so I took a look at the factory wiring diagram book to refresh my aging brain.

So just so you know exactly what you accomplished and for the benefit of others. The 99 FSM shows an "ADD control relay" (likely the same as "transmission control relay" in 2000) located behind the pass side kick panel. It is a typical 5 wire relay with 2 wires for the relay coil and 3 for a "common, normally open and normally closed contact set. It controls the 2 ADD VSV's and the neg side of the relay coil additionally provides a control loop through the 4wd, 4lo switches and some mysterious input to the ECM labeled 4wd (the part I originally questioned years ago). Today, in hindsight it looks as if the ECM input was used for coordinating things on tucks with some combination of auto trans, ABS and e-locker with their associated wiring and controllers.

The wire colors and purpose are as follows.

2-black/yellow trace, one is 12v to relay coil, the other is 12v to the "common" of the contact set

1-light green, from the NC contact powers the VSV responsible for "disconnecting" the diff

1-blue/red trace, the other VSV responsible for "connecting" the diff

1-red/white trace, a control loop through the 4wd, 4lo switches and the ECM 4wd terminal

By cutting a switch into the blue/red trace wire and the switch open you disable VSV #4 thus prohibiting the ADD actuator from "connecting" the pass side axle

 

sub'd, looking to do this soon

 

I see. What I did was turn the key on with the transfer in 2wd high and checked to see if the red/blue changed when I engaged into 4wd high. It showed a positive 12 volts. In essence am I doing the exact same thing as your method just a wire inside the cab? I tested everything and it worked and was apparent I have control over the front as I could spin the back wheels with it unlocked. I just don't want to cause harm to my truck. I mainly want it for the ability of backing up trailers and such without slipping the clutch to much.

 

Yes sir, you got it, with no chance of affecting any other systems. In fact it's all coming back to me now. I did the same deal at the relay, I just used the extra pole on my switch to power VSV #2 when when VSV #4 is switched off. It was totally unnecessary.
The whole deal with cutting in a switch in the red/white trace wire near the 4wd switch was just off the top of my head at the moment to get you going. Turns out you got it (the correct way) on your own. There is a risk of switching that red/wt wire at other points (like near the relay) depending on the exact configuration of the truck. In 99 alone that circuit has at least 3 variants depending on the factory build combination of engine, transmission, transfer and locker. Putting a switch at the wrong point could disable other systems.

Good job and go wrestle some trailers.

 

Ok, that's what I'm looking for, THANK-YOU!

 

Hey Dirty Pool, Can you show some pictures of where you mounted the switch for the ADD for the 2 lo? Or anyone else. I'd like to get some ideas as to where I should put mine.

 

I have switches mounted where the clock is. I also have some mounted on a plate beside the gear shifter. Also have some mounted on the drivers door where the power mirror control would be.

 

Little "bat handle" switches.

Left sw for the anytime locker (not really needed).
Right sw for ADD disable.

It was tough drilling the holes on a 2 week old truck.

 

That actually looks pretty good. Fairly Discreet. Theres alot of ARB swith covers out there that look ugly on the 1st gen IMO. Thought about putting switches in the by the gear shifter but I feel they would be pressed too often by random crap. Also cant believe you started modding your truck within 2 weeks or purchase! Thanks for the picture!