JHupp

Ok, I had a quick thought today on this, when I was reading a writeup on a 2002 $4runner with the exact same system I have in mine, the center differential lock. Now, I am not terribly educated in cars as one could see. I make many mistake. I also do not want to turn into a center differential lock discussion, as I have searched. But in this review, located here it says that

"A center differential lock switch located on the instrument panel allows locking and unlocking of the center differential by pressing a button. This lets the driver make the choice of positively locking both rear wheels and one of the fronts together, meaning at least three tires will be clawing their way through muck or slush."

Which is exactly what I was going to buy a locker for. Am I just terribly naie, is this a bad review, and do I even need a rear locker anymore. Even if it was like a 70/30 split between the rear wheels, I would be elated. If someone could just tell me whether I am right or wrong, or even point me to a good link, I would be happy. Thanks,
Jason

JHupp

Yeah, also the consenus I get from other boards is

"ATRAC is equally effective as any limited-slip differential. However, it is not as effective as a pure locker."

"From what I've read on the subject, I would choose ATRAC on the front and rear axels, over a single rear LSD. Less maintainance, better traciton up front. Add some great tires, and it's all good."

"With ATRAC, it's like having LSD on the front and rear axles. With the center diff locked, the 4runner is quite capable! ATRAC is such an elegant and simple design...no extra stuff...it just uses the existing technology (4-channel ABS, ABS sensors, etc.) to create a LSD."

"50% of the power will go to the wheel with traction, the other 50% will be dissipated as heat in the brake of the other wheel. This is because, with the open differential, the torque is always split 50/50. To get torque (thus power) to the wheel with traction to the ground you need the same torque on the other side of the open differential to be supplied by the brake."

from
http://www.toyota-4runner.org/showth...&threadid=5036

everyone on most boards seem to agree that it is fairly capable, and it seems to be exactly the same as a powertrax would be. If you think otheriwse, please let me know, as I may very well be wrong, but from the thoughts I hear about ATRAC and the center differential lock it seems to be a capable off road rig the way it stands. Like I said, I am a complete novice, so dont blast me if I am wrong, or this has been explained somewhere(i did search)

bob200587

If you're 4runner has 4wd you shouldn't have a center diff, and if you do you should have a button to engage it already.

ecchamberlin

I cannot tell you exactly how it works but our 01's do have a center dif locker and mine works very well. I do know that there is a small electrical motor on the back of our T-case and that is the "locker". It is also the reason we cannot install crawler boxes.
I have had many guys with true lockers tell me that they thought I had a rear locker the way my Runner was able to keep up with them. Now I have pushed it to the point where the rear will slip.
So I agree with you that a rear locker is a real added bonus to the system we have but if you are not going to really push it you shouldn't need it. With the selectable rear locker it will be the best of both worlds because we have VSC which on snow and ice roads is a very nice feature and then in 4 low this system is disabled to let us control wheel spin ourselves.

Mr. Bob

I thought only AWD vehicles had center diff locks??

hillbilly

The center diff lock does nothing but synchronize the front and rear axles and is intended to mimic AWD systems. The center diff lock has no effect on the power ratio provided to each wheel on the same axle. The front & rear diffs on 01+'s are effectively open. The 01+'s A-Trac uses the ABS systems to apply braking force to the free spinning wheel in attempts to force torque to the other wheel on the same axle. In my opinion A-Trac has a very adverse affect on momentum, especially in deep snow/mud.

JHupp

Yeah, I have never wheeled with it before. I went off-road, in a little bit of mud with it, and was dissapointed that I couldnt really burn it out, so I installed the kill switch and have been disabling it off-road. I am going to give it a shot when I go to Paragon next weekend. Down the road I think I may go with a selectable locker like an ARB if I find myself needing one. Right now I don't think I do, I'm still just starting out. Also, did anyone read the article about the FJ doing Rubicon Trail with ATRAC in Toyota 4wd owner?

heddleston

Correct me if I am wrong, I don't know a whole lot about the 01's as I have a 99 but I thought the only reason to have a center diff is becuse you have an AWD system. Toyota calls it full time 4wd in the crusiers but AWD and full time 4wd are basically the same, the difference being that you have a transfer case. The button that locks the center diff is different than the e-lockers rr diff lock. The center diff in lock splits power 50/50 front and rear for off road suaitations, but when the center diff is not locked is splits power as needed to the front axle, rear axle to deal with drive line binding.
Since you have this system I don't think you can run any front locker other then an ARB or cable locker. You have a similar system to a land crusier. I think that you can find some info on this subject at slee off-road

Have you ever been able to smoke the tires on pavement? If you can't it's AWD and you can't run a front locker other than an ARB, cable.

Jonathan

JHupp

From ehere it gets complicated. The center differentials is characteristic of an AWD yes. Howveer on the 01s and 02s it does not run full time. The center differential is efectively off unless activated electronically. The truck normally runs in 2 wheel rear drive. Once the 4wd/awd is actvated the center diff comes on and adds something like a 40/60 power split between the front and rear. locking the center diff makes it a true 4x4 with a 50/50 power split front and rear. This is the gist of it I get. You could not run a full time locker up front. It would have to be an LSD or a selectable. Even though there is no power going t the front wheels when in 2wd, the front diff behaves as if it were in neitral, and therefore the locker would be constantly ratcheting. This is what I get from the whole system. I have since decided not to lock it, as the ATRAC has been working well for me. When I get so far as to get it stuck, I will probably ge selectable lockers, hopefully they will make an electrac by then.

heddleston

The full circle. Are you still going to run the rear locker, I would like to know the outcome. The ADD is interesting, I halfway understand it…I just don’t know how jeeps are running front lockers and we can’t…..or the 4runners with the selectable 4wd can’t. Maybe Napoleon047 can explain how we disable the ADD, is it with a vacuum hose (I thought that’s how the jeeps do it) or what do you have to do?

Bighead

You can run a front locker with ADD...I did for about a year before I went to manual hubs and I am far from being the only one to do so. My only concern during that year was activating my front locker by accident while at highway speeds.

JHupp: If you are that concerned about money, why don't you just hold off on the locker install and wheel your 4Runner with the computer only? Once you decide the types of trails you will be hitting you can then decide what type or amount of lockers you need to be successful. You have a pretty capable platform as it is with ATRAC...use it a bit before dumping too much money down on something you may be swapping out in 6 months.

ecchamberlin

I think this is some of the best advice on this thread so far. I have been shocked and shocked a lot of others with what a open diff'd 2001 can do. Many have thought I had at least a rear locker.
I will wait until I find specific types of terrain I cannot handle with factory gear before choosing a locker .

Belize Off Road Team

ok, i wanna run kinda the same set-up, it is my daily driver and i do off road trips every weekend, sometimes a couple times a week, so i am looking at Detroit EZ-locker front and rear...now i have ADD manual tranny, can i run with a ez-locker up front? and i know i can in the rear and be happy about it, but it is the question of putting it up front that concerns me.