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Discussion Starter · #1 ·
can i get a front locker for my fj? if so can i have a-trac on when i have just the front locker on?,and not the rear? can you have a-trac on when you have rear diff on? thanks:rocker:
 

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can i get a front locker for my fj? if so can i have a-trac on when i have just the front locker on?,and not the rear? can you have a-trac on when you have rear diff on? thanks:rocker:
THe answers to your questions:

1.yes

2. yes, but why ? Can't see a situation to use the front locker without the rear on too, and then A-trac is moot.

3.Depends. Early release FJCs (3/06-12/06 or so) have to be modified to keep A-trac on with the rear locker engaged (see "A-Trac Hack threads from long ago). Starting with the TRD FJC, they were wired to allow A-trac to remain engaged with the rear locker on.

hope that helps...:rocker:
 

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Yes, you can get a front locker for your FJC (ARB being at least one)

ATRAC when locked in front, when you are locked, both wheels spin equally no matter what. If ATRAC sensed spinning of one wheel (as the driver's front as an example), it would try to brake that wheel in an attempt to put more power to the non-spinning wheel but with the front locked, if one wheel is spinning, so is the other wheel. This equals no effect.

ATRAC on front but not on rear, haven't seen that modification yet.

ATRAC w/rear diff locked, early build's had to be "hacked", newer builds, yes.

Check the sticky thread on all you needed to know about ATRAC...
 

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I have the ARB front locker. You have to drop your gearing to at least 456. If you get locked up front and rear, you'll never use A-trac again! I know a bunch of people are going to hit me up and argue this point and tell me how great A Trac is because you can still turn etc....etc, but I've run both in tons of situations and my locker set up crushes A Trac every time. You can have my A trac.
 

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Discussion Starter · #5 ·
i dont get it!??? im new with the FJ but i studyd it for ever...! and if i had the front locker on could i have the a trac on for the back? i just whant to know,,:cowfrown:
 

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If you install a front locker and have ATRAC you could have the front locker engaged and the ATRAC on. The ATRAC would then work on both front and rear. I cant tell you the results on the front end if ATRAC was working on it while the locker is engaged. If a front tire spins ATRAC is going to try and add brakes to it, which in that case would be counter productive IMO.
 

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I have the ARB front locker. You have to drop your gearing to at least 456. If you get locked up front and rear, you'll never use A-trac again! I know a bunch of people are going to hit me up and argue this point and tell me how great A Trac is because you can still turn etc....etc, but I've run both in tons of situations and my locker set up crushes A Trac every time. You can have my A trac.


did you get the JT 4.56 gears for your FJ? It mentions needing an extra housing part for the larger gears.....what did that cost you to get gears installed with all parts?
I am thinking about doing the 4.56 gears to get back some grunt and pep since adding my larger tires.
 

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You have to drop your gearing to at least 456
Incorrect. ARB has two options for front lockers for the FJ. I think 3:90 is the gear ratio threshold that decides which one you need. I installed an ARB front locker with the stock gearing on my auto (3:73 is the OEM ratio I think), but when I re-geared (to 4:10's) I had to purchase the other ARB unit, which also works with the 4:56 and 4:88 gears as well.

Jim
 

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o duh...stupid me...hahaha ok some people call it black chery or is it brick red>?
The black cherry is the older color that is kind of a dark red. The newer brick red color is a brighter red than the older one. The newer one actually looks red, the black cherry looks black until you see it in the sun or up close.:cool:
 

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Discussion Starter · #13 ·
The black cherry is the older color that is kind of a dark red. The newer brick red color is a brighter red than the older one. The newer one actually looks red, the black cherry looks black until you see it in the sun or up close.:cool:
thanks..................................... i have a black chery...!
 

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just cause I'm curious...Do yall think the a-trac would still limit slippage even if the diffs were locked? Locked or not wouldn't it try to keep you from spinnin?
 

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I have the ARB front locker. You have to drop your gearing to at least 456. If you get locked up front and rear, you'll never use A-trac again! I know a bunch of people are going to hit me up and argue this point and tell me how great A Trac is because you can still turn etc....etc, but I've run both in tons of situations and my locker set up crushes A Trac every time. You can have my A trac.
I can't argue one way or the other cause I'm not locked up front, but. Have you tried to run both at the same time?
 

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A-track is activated when there is wheel slippage, as calculated by the antilock brake control unit (abs ecu) seeing a different wheel speed signal. Locking the front and rear will cause all four wheels to spin at the same rate, even when slipping. The abs ecu will see this as normal, no wheels are slipping, no a-track applied. The factory rear locker is tied into the abs system, and is regulated so that atrack does not apply brakes to the rear when the rear diff is locked. An ARB front locker will not have the ability to isolate braking from the front wheels to keep the axles from binding, as it is not tied into the abs system.

If you are locked up front and not in the rear and have atrack on, applying brakes to the front and not the the rear will cause axles to break. End of story.
 

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"If you are locked up front and not in the rear and have atrack on, applying brakes to the front and not the the rear will cause axles to break. End of story."


please explain this, I am lost.....I have been thinking of maybe adding a front locker but dont want any issues down the road......will a front locker damage the FJ with use? how can you differtiate between braking to front and rear?
 

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If you are locked up front and not in the rear and have atrack on, applying brakes to the front and not the the rear will cause axles to break. End of story.
I agree with your first paragraph....but the last one, I too am confused about.

How?

If the front is locked and the rear is not and you have atrack on.....the atrack will simply not actuate the front brake calipers since no difference in wheel speed will occur b/c of the ARB. Therefore, the only thing the atrac will be controlling is the rear axle and it will function as normal (I'd assume) braking whichever rear wheel is spinning. It's just like the current system of having the rear end locked with the Atrack on.....and that doesn't break axles. Is this incorrect?

*******************************************************
It's important to note that if any "automatic" locking diff like a Detroit or Lockright or Aussie becomes available for the FJC front end....it will have very slightly different amounts of wheel speed by the very design of the auto locker....so they should be avoided if use with the atrac system in conjunction with the front locker is intended. Of course that also depends upon how many tire revolutions it takes for atrac to engage, but I digress. As someone already mentioned in this thread, once you have f/r lockers, there's almost zero reason to ever use Atrac anyway.

Sean
 

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In theory yes, but, the problem is this. The rear locker is integrated with the A-track system. It knows not to engage it to the rear ever with the locker locked. If you put a locker in the front, the system does not know it is installed. (Why would you ever have the front locked and the rear unlocked??)

Just becuase it is locked in the front does not mean it will not encounter wheelspin. Im my experience the front is usualy the first to loose traction. Asa the fronts start to slip, A-track will apply braking pressure to the front, transferring traction to the rear. This is where you start to encounter driveline binding. My personal opinion is this: either be fully locked and carefull, or rear locked with a-track. You can try anything you would like, and hell, it may work. I am simply expressing my opinion based on problems I have seen working on four wheel drive vehicles.




I agree with your first paragraph....but the last one, I too am confused about.

How?

If the front is locked and the rear is not and you have atrack on.....the atrack will simply not actuate the front brake calipers since no difference in wheel speed will occur b/c of the ARB. Therefore, the only thing the atrac will be controlling is the rear axle and it will function as normal (I'd assume) braking whichever rear wheel is spinning. It's just like the current system of having the rear end locked with the Atrack on.....and that doesn't break axles. Is this incorrect?

*******************************************************
It's important to note that if any "automatic" locking diff like a Detroit or Lockright or Aussie becomes available for the FJC front end....it will have very slightly different amounts of wheel speed by the very design of the auto locker....so they should be avoided if use with the atrac system in conjunction with the front locker is intended. Of course that also depends upon how many tire revolutions it takes for atrac to engage, but I digress. As someone already mentioned in this thread, once you have f/r lockers, there's almost zero reason to ever use Atrac anyway.

Sean
 
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