I am considering buying a Sequoia so I can have more room, more power and some sort of differential control. My 4Runner is great but is a tad underpowered, plus I have an open diff.

I read on the thorough and excellent Tundra/Sequoia FAQ that the TRAC control turns off when it's in 4 low. Is this really true and does this not defeat the purpose of having traction control in the first place? It seems this would revert the truck back to an open diff system. True?

I would love to have more traction in the snow and hate the lack of a limited slip or locking diff in my 4Runner. One more question: How good are the ARB's and do they make them for my '99 4Runner with 5 speed?

Thanks in advance for the help!

 

The whole purpose of Trac is to limit skidding through engine power (through the throttle body) and braking. Usually in 4Low your not going fast enough for one for the above mentioned components to cause a factor, second 4Low is really used for extreme situations of 4WD, like crawling and such, so you really don't want traction control so much on those situation, as sometimes you DO want to slip, especially sliding down a hill.

The second question, I am almost 99.9% sure they do make an ARB for the '99 4Runner, you are talking about the locker right? I have read about someone installing a front one, in a 2000, so i imagine one out there for the rear. I would look for you, but work internet bites and is really slow compared to cable modem at home. Look on ARB's website
Oh last question, ya I heard good things about them, all positive.

 

IIRC, you can get ARB lockers for both front and rear of all model year 4Runners up to 2002. Not sure about 2003 and beyond. Talk to Mike at www.xtremeoff-road.com. Best prices around and great service as the icing on the cake.

 

Thanks for your replies! I have been looking at Sequoias this evening...

 

So you got an '02 since you last posted, I take it?

I didn't read through the FAQ link you posted, but if what you said was true, they are incorrect. If you still need to know how they work, then I have this:

For the Sequoia:

TRAC can NEVER be disabled

It has a dedicated VSC disable button (can't disable it in 2WD)

You cannot be a conventional 4WD (center diff locked) in high range, but only AWD. The only way to lock the center diff is by going to low range, which locks it automatically.

Good thing you got an '02, as the dedicated VSC computer was upgraded for that year making it much less sensitive--trust me, a good thing.

The TRAC system is no substitute for a locker, but waaaay better than conventional open diffs. Not sure that will make any difference as your 4Runner should be the desired trail rig. I would guess, anyway.

The TRAC isn't controlled by engine dethrottling, but purely ABS and braking a wheel(s). VSC is related to the engine dethrottling.

You can skid all you want in low range where ABS is greatly reduced in sensitivity, as has been on the 4Runners.

How good are ARB's? They're the best and right there alongside the factory e-lockers. Fully selectable is the name of the game. Yes, they make them (front and rear) for the 'Runners. And yes, Mike is the guy to talk to.

 

Darren,

I do appreciate your thorough reply. Thanks!

Yup, I bought a used '02 Sequoia. It rides very well, but the handling is not as precise as my 4Runner which was not as precise as my old Pathfinder which was...you get the idea.

We'll see how good this thing is in the snow. I have a steep driveway and need to tow a car up it, possibly in snow this winter, for an excursion to Sebring, FL.

 

Very good, Mark.

I now see you're getting rid of the 4Runner.

Here's a pretty active Sequoia forum if you need, until this place outgrows that one anyway.

Is your driveway this steep?:





If not, you should be okay!

 

Um yes it can, I haven't check out the Sequoia's mechanisms but TRAC (if it stands for traction control can be turned off) it's has to have a switch; most cars or trucks that have this have a switch to do so.

TRAC and VSC are basically the same principle (maintaining traction on the ground to the wheels) but from what I remember I saw at the dealer the 4Runner uses VSC, while the Sequoia uses TRAC, still the same ideology, what mechanisms they use though is beyond what I know as I haven't studied Toyota specific traction control electronics, that's the T-ten program, I am only in the basic auto program. But still the general industry of traction control utilizes engine dethrottling and braking.

 

You have a bit more reading to do. Everything you stated is incorrect, save the last word about it utilizing braking. TRAC can only be disabled on 2WD 4Runners (maybe Sequoias, too), but I have to say I have no interest in those. Post your thoughts on the 4Runner board if you'd like.

I'm really not sure why you're trying to disagree with one who actually owns a rig with this stuff. Wouldn't you think I know how it works? If not, okay.

 

Not trying to disagree with you, dude , but I just finished a semsester on this stuff. Alright you forced me to do a bit of research on the net. Your right about the 4WD not having a defeatable switch, that sucks! I also was wrong about the 4Runner and Sequoia, the Seq. has both systems. But still, I stand behind my statement of VSC and TRAC, basically being the same principle, different names because different computers utilizings different mechanisms, they are still all integrated. Taken from Truck World Article

Vehicle skid control --- or VSC--- helps to maintain cornering stability in situations where the vehicle is about to lose traction and skid sideways. VSC senses when too much steering input is applied while the vehicle is traveling over poor-traction road surfaces, such as loose dirt, pooled water, or ice. The system automatically reduces engine output and independently applies braking power as necessary to each of the four wheels to help maintain vehicle stability and driver control. VSC is now standard on both Land Cruiser and 4Runner and will be standard equipment on both 2WD and 4WD Sequoias.

Traction control is standard on both four-wheel and two-wheel drive vehicles. Using the same wheel sensors used for VSC, the four-wheel drive A-TRAC system maintains wheel traction on slippery surfaces, by automatically applying brake pressure to each wheel, independently. A-TRAC adjusts braking influence to individual tire grip at all four corners.

Two-wheel drive Sequoia features TRAC, a system similar in operation to A-TRAC, but dedicated to rear wheels only. One major difference between the two is that the A-TRAC system is full-time, whereas the two-wheel drive TRAC system is defeatable. This feature gives the TRAC system an added measure of engine torque in sandy or muddy conditions at low speeds.

 

I know this is late but

Yes there is a button to turn the system off but it is automatically turned off when put into 4-low

 

Hey, guys,

Thanks for the responses. Somehow my email notification gopt turned off. Weird.

Darren - That photo can't be for real! No, my driveway is considerably less steep than that.

I have been so busy I haven't been able to crack open the Sequoia manual for very long. I need to checck out the VSC/TRAC section, as these seem to be the same thing and operate under the same principles but are called different things under different situations.