4low-trac

Nice Video, you didn't just lift a wheel you almost did a stoppie..lol! I would have liked to hear the sound of the truck but it definitely looks like an awesome mod.

 

Can someone explain how the switch part works? Are you able to use the VSC switch or are you guys insalling a switch directly on the wire in the glove box?

 

The car with the streaks is the TRAC button. In 4lo you automatically have the lsd frt/rr working. the turn it off press and hold the button until the light on the dash comes on indicating trac is off. It will be like you are in 4lo without the wire mod. lsd off

 

They are putting a switch to the yellow-black wire in the 4wd ECU so they can turn the mod on and off. If you don't put a switch in you can still switch off the TRAC/VSC by using the VSC switch as you normally would when you are in 2wd or 4hi.

If you refer to (Yes I know this is the wiring diagram for an 06 not an 09) The transfer shift actuator assembly (The actuator that shifts the transfer case between 2H 4H and 4L) sends it's position information back to the 4WD ECU but it only tells the 4WD ECU whether or not it's in 2HI or 4HI. It doesn't concern itself with with whether it's 4HI or 4Lo it still sends the signal that it's in 4HI even though the actual position of the actuator may be in 4Lo. This is how we can trick the ECU into thinking it's in 4HI so the TRAC system doesn't throttle back engine power because we know that in 4HI the TRAC system doesn't interfere with throttle position. The TRAC system takes over throttle control when the 4WD selector switch on your dash is in the 4LO position and sends that position information to the Engine ECU via the 4wd indicator. It doesn't have to do with whether or not the actuator is actually in the 4Lo or 4Hi position because as I already explained the actuator only tells the ECU it's in 2H or 4H. So by disconnecting this yellow-black wire you are preventing the signal from the 4WD indicator from telling the Engine ECU the tranfer case is in 4L0.

This is my interpretation of how the mod works from analyzing how the 4WD actuator / electronics function and from reviewing the schematics. I'm not an engineer so I definitely don't know all! Anyone who does this mod is doing it at their own risk and shouldn't blame some guy on the internet for telling them to do it if something should go south.

 

The switch is redundant as you can turn off the mod simply by pressing the vsc switch.

If you look at page three of the schematics its the yellow wire labeled 17. When you snip this wire the signal that 4lo has been actuated wont make it to the CPU. that is why the 4lo light flashes. the cpu thinks there was an issue with 4lo engagement, keeping 4hi Trac activated giving lsd front and rear. When you put the truck in gear your deff in 4lo. if the truck does not go into 4lo you will still get the beeping indicating an error.

 

Ya, that's how I understand it just couldn't put it as simply..lol. The only reason I would put a switch on the wire is so that I could turn the mod off for times when I take it in for service and they need to inspect the 4WD system (They would be confused as to why the 4Lo light is flashing) and if I let someone else drive it as they may also be confused.

Sadly I live in a small town in the flat prairie with no place to test the mod.

 

totally understood. I agree on the dealership but as for letting someone use the truck they wouldnt know if it was normal or not. Come to think of it, if i let someone barrow my truck they sure as hell better not need to put her in 4lo. It would be really easy the mount a switch by the glove box.

 

My understanding is that it tells the skid control computer (seperate unit) that it is still in 4H. Either way just a signal wire.

 

Alright guys, I have some questions before I go and do this.

I live in florida, so there are no hills or rocks anywhere to be found. Most if not all of my traction issues I encounter are mud/water or white sand. Would I benefit from doing this mod? I can't remember the last time I was in 4LO in mud. Should I be?

 

If you are using 4 high, the TRAC system operates all the time.
I found it was very useful anytime the terrain was uneven. Particularly chewing my way out of mud holes at funny angles onto sand, the truck would always chew it's way out. I found the truck to very weak with just the open diffs, and road biased dunlops, (my '09 4 cyl). After the mod, the truck was so impressive, the people at my local off road area couldn't believe what I was able to go through.

 

If you get bogged down and stop, 4hi probably isnt low enough to really chew through the mud. especially uphill. 4lo allows you to really sling the mud without bogging the engine and with the mod 4lo trac will get through most anything as long a one tire has traction. With the mod and the truck in 4lo all four wheels will bite giving you real close to having lockers. Not quite the same, but close and free.

 

Also, if you want to see if it makes a differance after you do the mod you can turn it off by putting the truck in 4lo and holding the vsc button. it will turn the TRAC off and you can get yourself stuck, lol. I did it in some sand got pretty buried and pressed the button again to reactivate TRAC and manged to floor it and slowly drive out, the point is i was hopelessly stuck and the trac in 4lo got me out. Its almost like the differance between 2wd and 4wd.

 

I did this mod and wired a switch inline with the wire that people are cutting, just in case it does somthing I don't like, flick the switch and it returns to normal. As you can see, I put the switch just inside the glove box.

 

Where can you pick up a switch like that at? Any particular type? Never done my own electrical work before.

 

a spst (single pole, single throw) typical on/ off switch from radio shack will work fine.it will have 2 pins on the bottom. if the switch clicks twice (once in the middle) you dont want it.

 

I got that one at a hardware store. It is an on/off switch. Very simple install.

 

I wish I would have read about this before I hit the trail today!! I had a patch of snow that was too deep to plow through and I tried to use a patch of dry ground off to the side but once the snow side of the truck broke loose I wasn't going anywhere. Had I had traction on the dry side I could have crawled through no problem. Am I getting how this works right? This would brake the tire with no traction and allow the differential to provide power to the tires with traction?

 

It is a lots smoother and quieter than ATRAC. More effective than just having a rear locker. Got stuck today, locker wouldn't get me out, ATRAC did. It was a noisy operation under full throttle. whereas TRAC is smooth.....

 

Yes it transfers power to the side with traction. Did you have the truck in 4hi or 4lo. if you were in 4hi you could prolly make it in 1st gear and flooring it because the TRAC is activated in 4hi. the mod make TRAC available in 4lo

 

wish i woulda known about this before i got stuck a bunch the other weekend.

anyone try enabling actual ATRAC instead of this?