Completely Confused about 4WD ATRAC

C

Cruiser13

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HELP! This is not making any sense to me. I have an '02 Land Cruiser. It is always in 4wd mode with ATRAC. You cannot turn it off.

I have an 07 Tundra. It is 2WD until you put it in 4H or 4L. That locks the center diff and turns on ATRAC. There is a button to turn off VSC, but not ATRAC.

Now, I have an '11 4R Limited. It is an H4F (open diff) until you either lock the center (H4L) or go to 4L (L4L).

If in H4H, is ATRAC on or off? Pg 230 of the manual states that to activate ATRAC, put it into L4L and then press ATRAC. This makes no sense to me! Why only in low? Why would you have to activate it? Shouldn't it be on all the time?

Then there are instructions for turning off ATRAC?! Why would you want to turn it off, so you can spin your wheels?
 
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Your issue seems to be you don't understand the differences on your 4Runner between traction control and ATRAC. Very different systems used at different times. I have a meeting and will let someone else explain it, or just search, should be lots of threads on it.
 
A-Trac is a traction aid for steep, rutted, slippery situations when you would most likely be in 4low similiar to a locker. Also when in 4wheel locked mode you do not always need it, hence the on/off button.

A-Trac is off in both 4H and 4L until you push the botton and the Atrac light comes on on your dash.
 
Cruiser13 said:
HELP! This is not making any sense to me. I have an '02 Land Cruiser. It is always in 4wd mode with ATRAC. You cannot turn it off.

I have an 07 Tundra. It is 2WD until you put it in 4H or 4L. That locks the center diff and turns on ATRAC. There is a button to turn off VSC, but not ATRAC.

Now, I have an '11 4R Limited. It is an H4F (open diff) until you either lock the center (H4L) or go to 4L (L4L).

If in H4H, is ATRAC on or off? Pg 230 of the manual states that to activate ATRAC, put it into L4L and then press ATRAC. This makes no sense to me! Why only in low? Why would you have to activate it? Shouldn't it be on all the time?

Then there are instructions for turning off ATRAC?! Why would you want to turn it off, so you can spin your wheels?
Click to expand...

Sounds like your confusing ATRAC and TRAC on the 5th Gens. As to where you would possibly want to shut TRAC off ......when you are in mud or sand where you don't want it cutting engine power or having fun doing donuts/drifting in an open snowy parking lot or field.

Here's a little better explanation....... http://www.toyota-4runner.org/5th-g...part-time-4wd-trail-edition-3.html#post714173
 
Cruiser13 said:
Then there are instructions for turning off ATRAC?! Why would you want to turn it off, so you can spin your wheels?
Click to expand...

You have ATRAC & TRAC on your 4R - 2 different systems - Read up on them and you will see the differences and in the process answer your own question, and learn about the vehicle you own and drive. Knowledge is power!
 
Thanks.

ATRAC is not limited to LO-only on the other vehicles. I'm still puzzled by this and it is the reason I assumed it ought to be on by default, negating any reason for an on/off switch.

BTW, can anyone think of a situation where you would want TRAC off, but VSC on?
 
Cruiser13 said:
Thanks.

ATRAC is not limited to LO-only on the other vehicles. I'm still puzzled by this and it is the reason I assumed it ought to be on by default, negating any reason for an on/off switch.

BTW, can anyone think of a situation where you would want TRAC off, but VSC on?
Click to expand...

They changed the terminology in 2009 I believe as they used to call what is TRAC now, ATRAC.

I turn TRAC off when I want to keep the RPM's up and keep it moving thru Mud holes/Soft sand as TRAC throttles back the engine and applies the brakes.
From Toyota ...Toyota’s Traction Control sensors are activated when one of the wheels starts to slip. TRAC limits engine output and applies the brakes to the spinning wheel.

The only way to really learn is to bring your manual and go play with all the buttons and switches out in a snowy parking lot or muddy field to try to get an idea of what they're doing.
 
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harper7 said:
They changed the terminology in 2009 I believe as they used to call what is TRAC now, ATRAC.
Click to expand...

That would make a HUGE difference in my thinking. On my other Toyota's, ATRAC does NOT limit throttle- it only applies the brakes to prevent wheels spinning and power from going to the spinning wheel- which is, afterall, the purpose of 4WD. So 4WD would be next to worthless without ATRAC on both my LC and Tundra!

Now, if there is confusion on a dedicated Toyota forum, imagine how confused the average driver is. Toyota, if you are listening, please provide a cheat sheet!
 
I found this from other forum!!!
Copy and paste!



TRAction Control system . This is refering to TRAC. automatically helps prevent spinning of the rear wheels (2wd models) or 4 wheels (by adding brakes) when the vehicle is started or accelerated on slippery road surfaces.
Doesn't require push button activation. Works on it's own and is activated when the ignition is turned on. all FJ's have this whether 2 or 4wd model. On automatics, I am assuming this works in 2H or 4H, doesn't matter. If the system detects wheel spin, it adds brakes to increase traction.

A-TRAC is Active Traction Control system automatically helps prevent the spinning of 4 wheels when the vehicle is started or accelerated on slippery road surfaces. (basically same as TRAC, but only works in 4 Lo). To activated, hit the ATRAC switch, shift into Nuetral, and shift the 4x4 lever (short knob) into 4 LO. When in 4Lo, it detects wheel slippage and adds brakes accordingly to give added traction. Again, you must be in 4Lo and hit the "ATRAC" switch.



VSC (vehicle stability control) system : integrates the control of the systems such as ABS, TRACtion control, engine control, etc to prevent the vehicle from skidding when cornering on a slippery road surface or operating steering wheel abruptly.
VSC is activated when the vehicle reachs 9mph or 15km/h.
*VSC automatically turns off (VSC off light on dash comes on) when 4H/HL or 4Lo/LL is activated (AT/MT) or when the Rear Diff is locked.
 
My understanding is that ATRAC is like a Auto LSD but for 4wd. It brakes a slipping tire to help move the torque to the tire that has traction. Auto LSD is only for 2wd though. ATRAC for 4wd
 
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