A-TRAC or ARB?

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There is the "no cut" and the "cut" ATRAC hack. I did the cut version on mine, the thread I linked also has a link to the no cut version...

Rear Locker + ATRAC - Write up - TTORA Forum

Sorry for the thread Jack.

Jerry, I have a 2007 and am not sure if I can run atrac and the rear locker at the same time. If I'm looking at the picture in the link you posted correctly, if I put it in 4lo (automatic) then activate the locker, and then hit the atrack button, if I'm able to run both at the same time, I should have "A-Trac" and the red rear locker light come on at the same time on my gauge cluster. Does this sound correct? If I am not able to do it, if I go 4lo, locker, and then try the atrac, the atrac light wont light up. Sound reasonable?
 
Sorry for the thread Jack.

Jerry, I have a 2007 and am not sure if I can run atrac and the rear locker at the same time. If I'm looking at the picture in the link you posted correctly, if I put it in 4lo (automatic) then activate the locker, and then hit the atrack button, if I'm able to run both at the same time, I should have "A-Trac" and the red rear locker light come on at the same time on my gauge cluster. Does this sound correct? If I am not able to do it, if I go 4lo, locker, and then try the atrac, the atrac light wont light up. Sound reasonable?

If I recall, the build date for the change was 10/07.

Before that, you could not activate ATRAC with the rear locker locked. That is when the "ATRAC Hack" was developed. Then, both could not be used at the same time. If rear locker was locked, ATRAC was disabled (light goes out on the dash).

After, Toyota changed the ECU so that they could both be active at the same time and shows with the lights on the dash.

Yes, your dash should tell the story. Lock the rear, get the red light, push ATRAC button and if doesn't appear, you might consider doing one of the two hacks. If the lights are on, you are good to go, no need for the hack.

Make sense?...
 
If I recall, the build date for the change was 10/07. ...
Just double checked to make sure and mine was built in 07/07 and the A-Trac comes on with the Rear Locker engaged, no hack needed.
 
I wonder if this is something I could tackle on my own? Hmmm

It's easy, as long as you don't mind cutting your stock wiring harness. Follow the instructions very carefully (making absolutely positive you are cutting the right wire) and you will be fine.
 
I love my A-Trac. It's better then a posi. I leave it on all the time and then only engage the rear locker when needed.

Trucks with front lockers experience a higher incidence of CV failure. That also holds true if you move up to 35's w/o a front locker.
 
Trucks with front lockers experience a higher incidence of CV failure.

Particularly if you're too happy with the skinny pedal.

But if you're careful, and don't try to replace good wheeling technique with the locker and skinny pedal usage, you're not any more likely to break the CV's. I'm still running the factory original CV's on mine, with an ARB locker, 34" tires and 130,000 miles on it (and a heavy dose of wheeling too).
 
You sound like you share my wheeling philosophy, so maybe I should make the mods after all.

I was discouraged from doing it because one of our local club members went to 35's, 4.88's, lockers and the "unbreakable" CV's that he still broke regularly. He had the 6" RC lift and the All-Pro UCA's. His nickname on Mud is KrazyFJ, so maybe that is why? I remember following him with my 40 one day and backing away after watching him hammer it up over a steep and abrupt ledge.

Another club guy went to 35's after wheeling his first model year FJC safely for years and blew a CV within a few weeks. He also just had to replace the wheel bearing on that same side 6 months later.

Both guys mentioned above have 6 speeds with the full time case. The FT case undoubtedly adds more wear to the front end over time. The more direct coupling of a manual tranny will also add more abrupt torque peaks to the drivetrain than an auto.

Is yours automatic?
 
I'll add to Lee's idea...I never broke a CV, ran 35's, 4.88's and an ARB front locker. I watched people do it with 285's and no locker just because they had their front tire "pinched" and hammered the gas.

I got an email from the current owner of my old FJC, pics included a blown RCV CV and toasted Inchworm that I had upgraded with Marlin CroMo, oversized input & output shafts. Just proving that anything can be broken if one tries hard enough...
 
I remember following him with my 40 one day and backing away after watching him hammer it up over a steep and abrupt ledge.

Yep, that is pretty much the guaranteed way to break rear diffs, never mind front cv joints.


Is yours automatic?

Yes. I also have an Inchworm Lefty 4.7:1 transfer case which allows much more control and less abrupt surges in power.


Just proving that anything can be broken if one tries hard enough...

Absolutely! Sounds like we all know off-road FJC drivers like that. I don't get it, but some guys think it's macho to break stuff and proves what a great wheeler they are. :rolleyes:
 
As they said if you are careful with the application things can hold up well. To much throttle while on an incline caused me to bust the 4lo gear set in my lefty, CVs were fine, but not so much with the lefty.

Going from a situation where binded to momentarily having the drivetran break free (with enough throttle) to it immediatley binding again a second later cause enough of a load to shear off a few teeth.

My mistake not the transfercases.
 
I think the change was a few months earlier than that.
I had an June2007 built 2007 model year and A-trac and the rear locker worked together without having to do any hacks.

If I recall, the build date for the change was 10/07.

Before that, you could not activate ATRAC with the rear locker locked. That is when the "ATRAC Hack" was developed. Then, both could not be used at the same time. If rear locker was locked, ATRAC was disabled (light goes out on the dash).

After, Toyota changed the ECU so that they could both be active at the same time and shows with the lights on the dash.

Yes, your dash should tell the story. Lock the rear, get the red light, push ATRAC button and if doesn't appear, you might consider doing one of the two hacks. If the lights are on, you are good to go, no need for the hack.

Make sense?...
 
Yep, that is pretty much the guaranteed way to break rear diffs, never mind front cv joints.



Yes. I also have an Inchworm Lefty 4.7:1 transfer case which allows much more control and less abrupt surges in power.






Absolutely! Sounds like we all know off-road FJC drivers like that. I don't get it, but some guys think it's macho to break stuff and proves what a great wheeler they are. :rolleyes:

That 4.7 also multiplies the torque substantially, so you definitely are what I call a "smooth wheeler".
 
That 4.7 also multiplies the torque substantially, so you definitely are what I call a "smooth wheeler".

I'm pretty old, and got my fill of "fast" and "hurry" on motorcycles when I was a much younger man, so I'm all about smooth and slow now. :) I'm usually the tail gunner in any trail group I'm in because no one else wants to go as slow as I do.
 

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