charlie-5

As I sit here, I await delivery of my '07 TRD SE FJC w/manual trans. To help past the time, I've been considering all the various traction-enhancing tools the new rig has and I must admit, I'm a bit unclear as to all their functions respectively. Help me out here if you will.

As I understand it the vehicle in this guise is always in 4WD. In HL and LL, the center diff is deployed, transferring power more evenly front and rear. The locking rear diff spreads the power evenly between the two rear wheels. A-trac uses the computer to retard power to any spinning wheel and transfers power to those with bite.

Both rear locker and A-trac can only be used while in LL?
Isn't there some overlap in function?
What sorts of circs would suggest use one over the other?
What is Toyota talking about when they speak of intergrating (or syncronizing) the functions with the SE?

Thanks in advance for your expertise and opinions in these matters.

Good Times

Please see responses in red:

charlie-5

OK. Thanks Lance. By circs I meant circumstances. If I understand you, when the going gets tough, deploying both the rear locker and atrac would be the most effective plan with no advantage using one over the other. Sorry, but I thought I read that some technology was unique to the SE that coordinated the two systems...
Now if I could only expedite delivery out of Long Beach...

Good Times

the atrac on the fj is pretty impressive that the likelihood that you will need the rear locker will be very slim. I have an aftermarket rear locker from ARB and I rarely use it except during extreme circumstances. You will quickly learn what kind of terrain you will need the rear locker. I would suspect that you will encounter some body damages prior to even needing the rear locker.

Remember the atrac is a peudo software like locker in both the front and rear locker. In most scenarios you should be able to venture to a lot of trails without your rear locker. When you get stuck just engage and enjoy the ride

Since you're new to this, I would highly recommend you hit the trails w/ other more experienced drivers and learn from them. Read up on various offroading books available at your local book stores and read read read. By reading a lot you will gain the basic information on how to offroad property and go from there. The experience you gain will help you understand the limitations of your vehicle and build from there.

Don't forget that you should look into some sliders (aka rock rails) if you have not purchased the factory one.

Good luck!

charlie-5

Thanks. I'm in no hurry to bend anything, but it'll happen I'm sure. Oh, and in the "I'm sure I read that somewhere department" the query about snyc'ing came from a Press Release from Toyota announcing TRD's treatment of the FJ, dated 29 September.

"Additionally, TRD has synchronized the locking differential with Active Traction control. The locking rear differential no longer overides Active Traction control enabling the FJ Cruiser to navigate easier though boulders."

So it would seem there is little reason to apply Active Traction control andthe locking rear diff at the same time. Maybe the rear diff alone is better for some applications or perhaps its redundant...?

Good Times

actually you would want to run both the atrac and the rear locker as if you run just the rear locker you just have a locked rear + open front. by combining the atrac and the rear locker you get the locker rear + the atrac controlling the front which is like a pseudo front which I think is much better than an open front.

good luck

Corey

iTrader: (1)

You are lucky.
What Toyota means to the above is that both can be sued when in 4low.

On my FJ and all before the 50,000 production cycle, you can not.
If you have the A Trac on and then hit the e locker, A Trac turns off.
Bad Toyota

On all of the SE models and now ALL FJs being built, they work at the same time if you want.

Hope is not lost for the older FJs, there are two hacks.
One is done under the hood in less than 5 minutes by snipping and splicing a wire, the other is done in cab by applying one wire from a harness to 12v.

What that does is tell the ECU the locker is not engaged, and A Trac will work as long as it thinks Mr locker is off.

Your locker still lights up the dash though like it should with the hack.

I was considering the hack, but am not waiting to see of Toyota takes care of us.
They are aware of this, and many have called in a complaint and we have a case number on file.

RockRunner1

I have a question after reading all of the posts here. If I am reading all these correct it sounds like you guys are saying you can only use your A-trac in 4-low. Just an FYI but when we picked up our new FJ on 12-29-06 we were told the A-trac worked in 4-Hi, we have had plenty of opportunity to try it out here in snowy Denver and indeed it does work. We were also told that you could run the RR locker up to 45 mph, I don't believe that nor have I tried it yet but I will and will post the results. He did say you could run the A-trac with the RR at the same time. I did try that and it works, no blinking light.

Corey

iTrader: (1)

I have not heard of the A Trac working in 4 high, only in 4 low.

The rear locker has to be engaged at below 5 MPH, but you can drive faster than that with it on, but there really is no need to.

The locker is for traction purpsoes only as when you are slipping, and generaly you are in 4 low when using the locker.

We are still waiting to here from Toyota if they will give us new ECUs to syncro the A Trac and locker together on the older rigs.

RockRunner1

I agree with the locker but not to sure about the A-trac. We took it out Monday and were just driving, my wife hit the gas in the corner and what seemed like A-trac kicked in. It sounded a lot like the ABS on brakes but no brakes were aplied.

This will need more investigating.................Honey where are your keys???

Corey

iTrader: (1)

That is not A Trac.
To engage A Trac, one must be in 4WD Low, and you also have to hit the button on the lower dash next to the E locker button.

What you felt was the traction device called VSC.
It kicks in, you hear some clicking, and it applies the brakes to control your skid if needed.
I got to play around with that quite a bit when we had snow and ice awhile back.
I would try to get the rig sideways, but the VSC took over and steered the rig for me and put it back straight without any work on my part.
Now if it could only brew me a good cup of java.

I use that mode in 2WD to drive in the ice we had a month back.
In snow however, I put it into 4WD high to go to work in it.

Here is a thread on another forum with lots of info on this.
http://www.fjcruiserforums.com/forum...diff-lock.html

Here is a quote from the URL above.