auto LSD- what is the point?

FYI... auto lsd is the same action as trac. Trac is technically auto lsd and vsc.

mode 1 in your sig is slightly incorect. When the truck is in normal mode when you first turn it on without pushing any buttons the vsc is on however the rear lsd is not active. without pushing any buttons the rear diff is same a being open. (no brake input) When you push the button for auto lsd you turn vsc off until you reach 35mph then the vsc turns back on and you have TRAC. TRAC is always on in 4hi unless you press and hold the button.

 

Yoytoda, We had this lengthy discussion in another thread about whether TRAC could be considered a form of limited slip. I argued that it was not, however, after hearing all the discussion about it, I don't think its necessarily wrong to consider TRAC a from of limited slip.

To be very clear, we all know TRAC is not LSD, but we have to consider that the traction system does its job and will brake a slipping wheel, therefore one could say that its a from of LSD, its just not LSD.

 

According to the Toyota Canada website the off-road package is only available in the access cab not the double-cab shortbox or long. I love my truck but it's a pisser that Toyota really limits what options are available in Canada. The trucks are assembled in the same plants!!!!!!

 

Trac is just auto LSD combined with vsc. Im not saying trac isnt lsd im saying trac is more than lsd, it has vsc on too. in david ks sig his first mode says

"2WD: VSC and TRAC active, 'Vehicle Stability Contro'l and 'Traction Control' (Limited Slip Diff.)."

Im just saying that normally in 2wd, lsd is not active. therefore trac isnt active.

The two systems are auto lsd and vsc. when they are both active Toyota calls it trac.

 

Whats more stupid is they make Regular cab tacomas in fremont CA but 4x4 reg cabs cant be bought from cali. I had to buy mine in ny and the plate on the door says the truck is from fremont. Made right here but you cant even order one...stupid

 

Hmmmm... I got those modes from factory sheets and personal trials and 3+ months reading TW.

AUTO LSD (from my understanding) is a stronger, faster acting LSD than TRAC... in the same manner that A-TRAC is a stronger, faster acting LSD than TRAC.

Let's review so the data is correct...








Okay, as I read this NORMAL mode is TRAC ON (H2 and H4). TRAC is LSD using brake control, and only if the VSC button is pushed is TRAC turned off to either have AUTO LSD (quick push, H2 only) or Open Differntials (hold down 3+ seconds, H2 or H4).

TRAC and AUTO LSD are different functions, one is turned off so the other can turn on. AUTO LSD is a stonger form of LSD than TRAC...

In H4, there is no engine output regulation for TRAC, only brake control.

Review your data and let me know if the sheets are in error... I have found a big difference between TRAC ON (normal) and VSC OFF & TRAC OFF starting the truck from a stoplight and making a turn. When VSC & TRAC are OFF... the truck will fishtail if gassed, like my previous two Tacomas did. In the NORMAL (TRAC and VSC ON) mode, the truck may spin just a tiny bit, then the LSD takes over... big difference.

Thanks Yoytoda!

 

I just knew David would be jumping into this thread

Go get umm!! haha

 

I dont know if base models are different... as you know your trd offroad has a couple more buttons than my truck. I know that in normal mode, if i stomp on the gas, one wheels spins and then the throttle gets chopped. in snow, only one wheel spins until i press vsc off button. then auto lsd kick on the both rear wheels spin but still with throttle intervension

 

in the data sheet you provided it says in small print that vsc can not be turned off in 4lo however, i know for a fact that vsc auto lsd and trac are all off in 4lo

 

In my sig. it starts with:

2010 TRD OFF-ROAD 4WD DC with 9 drive modes (using VSC Off, A-TRAC & RR Diff Lock switches):

So, if your don't have a 2009 or newer 4WD OFF ROAD TRD, you may not have the 9 modes... I only use 3, except when seeing how they all work...

in H2, TRAC & VSC ON (Normal),

in H4 also TRAC & VSC ON (Normal),

in L4 I always have A-TRAC on (unreal 4 wheel drive).

I am trying to find a situation where the Rear Locker will ever add to what A-TRAC does... So, I will not engage the rear locker unless A-TRAC fails to get me somewhere or out of a 'stuck'.

 

YES, that is correct you can not turn it off... because it is already off!

 

The Toyota manual and sheets are poorly worded and written, and that is why all this confusion!

 

Actually there was a time i went offroading with some of the extreme guys and one guy was locked front and rear and couldnt make it up this one section... he turned the lockers off and used atrac and made it. atrac seems to be smoother and smart!!! thebrake system seems to allow the wheels to spin at slightly different speeds allowing for optimum traction. The way i look at it is if your locked and one wheel has to ride over a large rock it has to spin faster than the wheel on flat ground (more distance to travel) if your locked the wheel on flat surface will spin faster and cause slightly less traction. atrac the wheels can travel at slightly different speeds as long as both wheels have traction. toyota has it down...

 

You all have proved one thing for sure.... salesman don't know shit about the products they are selling. Had I found this site before my purchase probably would have went a different direction, those guys should just have a TW card to hand out, would make for a lot happier customers IMO.

 

Now this thread is getting great! whippersnapper, tegdog, and Yoytoda... GREAT ADDITIONS!

Oh, tegdog... when I got my '10, I was already sold on having the Off Road TRD, as it would be my third... so, there was no need to sell me on the features... I didn't know they were even on the truck! LOL

The assistant to my salesman did the checkout with me, and could not very well explain the VSC and A-TRAC buttons, the manual was no help either... That stuff I had to learn on my own... thanks to TW and then going to the desert and Baja as soon as I could!

 

Okay.

As a general statement, I'm not trying to win any arguments here, just further my understanding.

With regards to the above quoted text, I agree that in normal mode LSD is not active.

A point of clarification: TRAC itself is not a mode of operation--its a technology developed by BOSCH and licensed to Toyota. TRAC-OFF is a mode of operation.

My understanding was that when the truck starts up and in 2WD, TRAC and VSC are both active.

I know from personal experience that while in 2WD Normal that TRAC will brake a spinning wheel. (I tried to do donuts in the dirt.)

Part of the problem is that Toyota itself writes contradictory statements. Look at this quote from some of their technical documentation:

^If the VSC OFF Switch is pushed to enter TRAC-OFF mode thus enabling AUTO-LSD, then how the hell, is Auto-LSD using TRAC?

After reading the above statements, one could agree that TRAC-Off mode (Auto-LSD), TRAC is indeed enabled. This sounds absolutely ridiculous.

More Toyota technical statements:

The Toyota technical documentation below seems to me to be contradictory to the Toyota statements above.



Other opinions?

 

Hi Crom,

VSC is from Bosch and it uses TRAC (along with the many other sensors and things).

TRAC is LSD 'LITE' and AUTO LSD is LSD 'HEAVY'... TRAC gradually builds up and takes torque away from a loose wheel as it senses slippage. AUTO LSD is almost an instant torque transfer.

TRAC uses a vacuum booster to control brakes and AUTO LSD uses a hydraulic booster to control brakes.

Perhaps what Yoytoda was experiencing in that as you begin to move, the differential is briefly open, but will very soon take control if tires loose traction. IF TRAC is turned off (AUTO LSD ON), then the LSD is immediate to help you move from a stop and if one tire is slipping...

 

Sad but very true. . .after my third bs sounding answer, I quit asking. Why design and build all these cool "truck" features if only a small percentage of the customers actually know what they are or how they work?

I have two co-workers that just bought 2010 Tacomas. I started to explain some of these features and they looked at me like I was on ludes. They told me "no the dealer said bla bla bla" I guess we are the lucky ones.

 

TRAC is on in normal mode. TRAC has 2 modes, 1 with throttle intervention, 1 without. So you are both correct. TRAC has a limited slip effect, more pronounced when it is not limiting engine output.
Auto LSD is TRAC without the throttle intervention. No difference in the algorithms at all. Operating in 2WD or 4.

 

Here's a another point.... Does TRAC function the same on Sport models as it does on Off Road models?
No, but why not?......
Anybody.......








And no plagiarizing the correct answer David!