Why do I have auto LSD on my 4x4?

[NoDak]

at a stand still :

single push of the button turns off TRACtion, best if you need a running start up a iced incline as an example. it will re-engage at around 30 mph or until button is pushed again.

hold for 5-10 sec mode : will disengage TRACtion and VSC until the engine turned off or buttion is pushed again. VSC is the life saver for 95% of driving conditions, when you start sliding sideways, this saves your a.ss and applies the brakes to stop a slide so you don't do 180/360's down the road.

unless you know how to deal with those situations all the time where VSC hurts your chances of getting unstuck or prevent getting stuck or back sliding down an iced hill, don't turn off VSC.

at speed :

single push of the button turns off TRACtion, best if you need a running start up a iced incline as an example. it will re-engage at around 30 mph or until button is pushed again.

hold for 5-10 sec mode : does not work while moving.

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if you needing to turn off TRACtion and VSC, you should also be using H4L for best effect.

if your only turning off TRACtion, then H4F is all you need.


also the best way to remember :

H4F = High speed 4 wheel drive Free
H4L = High speed 4 wheel drive Locked
L4L = Low speed 4 wheel drive Locked

 

[voodoolord]

Thanks guys. I understand now.

 

[tornado_chase_hike]

I may be wrong but I believe if you just push the button it will turn it off up to 15 or so mph (then it will come back on). If you push and hold I think it will stay off until you push it again or restart the 4runner.

Yes, but at 25 mph. On my 2015 SR5 4WD, it does this. If you turn off TRAC by pushing the button (so, the TRAC light comes on), it will return to normal once I reach 25 mph. However, push and hold for 3 seconds and it turns off VSC too. In that case, they both stay off even above that speed.

I can't find it in the manual but I tried this a couple times today and got the same result.

 

[wfo9]

One more thing... It automatically turns off in 4Lo. But comes back on when back to 4Hi.

 

[96r50]

On the full-time 4WD High of the Limited, TRAC (not A-TRAC) and VSC (Vehicle Stability Control) are pretty much two parts of the same system. I think they are best distinguished by the sensors that activate them. From Toyota literature:

"Toyota’s VSC monitors steering angle and the direction your vehicle is traveling."

"Toyota’s TRAC sensors are activated when one of the drive wheels starts to slip."

That seems to be where the differences end:

When it senses that the front or rear wheels begin to lose traction, VSC reduces engine power and applies braking to selected wheels.

TRAC limits engine output and applies the brakes to the spinning wheel.

In the Limited's 4WD Low, VSC and TRAC are automatically turned off but you can activate A-TRAC.

That applies to all models across the board (even the PROs ). While VSC and TRAC do appear quite similar in operation their functions are distinct.

VSC keeps an eye on the direction the vehicle is moving and where the steering wheel is pointing in order to determine the difference between where the truck is actually moving and where the driver wants it to be going. When it senses too big a variance VSC cuts the power to the wheels and selectively applies brakes to one or more wheels to point the truck back in the direction it is moving. VSC doesn't care where the road is or how awesome you are at the Scandinavian flick, its only goal is to keep the nose of the truck pointed in the direction the truck is moving. Why? Because that's the safest way to crash into something. So in the winter when you give it a bit of extra gas around a corner to have some fun and you start sliding around the corner all VSC sees is that the truck is moving laterally instead of where the wheels are pointing. It then has a fit, cuts power to mitigate the skid and applies brakes to whichever wheels it needs to in order to point the truck back into the direction of travel. Even if that's a parked car or a giant snowman. Because for VSC, forwards travel is the best.

TRAC monitors the wheels for slip and when it sees one wheel spinning faster than the other it figures you're getting stuck and need some help. It then limits the engine so you can't just sit there bouncing off the redline and putting extra stress on the driveline. It also applies the brakes to the spinning wheel which should help force power across the open differential to the other wheel which presumably has more grip. TRAC is designed to help you get out of a mild stuck situation like having one tire off the shoulder in soft sand or loose snow. If you need more help than that you can shift into 4WD and if that doesn't work there's always 4WD Low and A-TRAC which is an "A"dvanced form of TRAC for more serious low traction scenarios.

 

[voodoolord]

That applies to all models across the board (even the PROs ). While VSC and TRAC do appear quite similar in operation their functions are distinct.

VSC keeps an eye on the direction the vehicle is moving and where the steering wheel is pointing in order to determine the difference between where the truck is actually moving and where the driver wants it to be going. When it senses too big a variance VSC cuts the power to the wheels and selectively applies brakes to one or more wheels to point the truck back in the direction it is moving. VSC doesn't care where the road is or how awesome you are at the Scandinavian flick, its only goal is to keep the nose of the truck pointed in the direction the truck is moving. Why? Because that's the safest way to crash into something. So in the winter when you give it a bit of extra gas around a corner to have some fun and you start sliding around the corner all VSC sees is that the truck is moving laterally instead of where the wheels are pointing. It then has a fit, cuts power to mitigate the skid and applies brakes to whichever wheels it needs to in order to point the truck back into the direction of travel. Even if that's a parked car or a giant snowman. Because for VSC, forwards travel is the best.

TRAC monitors the wheels for slip and when it sees one wheel spinning faster than the other it figures you're getting stuck and need some help. It then limits the engine so you can't just sit there bouncing off the redline and putting extra stress on the driveline. It also applies the brakes to the spinning wheel which should help force power across the open differential to the other wheel which presumably has more grip. TRAC is designed to help you get out of a mild stuck situation like having one tire off the shoulder in soft sand or loose snow. If you need more help than that you can shift into 4WD and if that doesn't work there's always 4WD Low and A-TRAC which is an "A"dvanced form of TRAC for more serious low traction scenarios.

Nice explanation. Sucks for the snowman.