Auto LSD

Good to here from a 2012 owner that they didn't change it!

 

Agree because A-TRAC is only works in low range and low range isn't good in sand. Mud is different but there are many kinds of mud.

 

Bottomless Everglades swamp mud!!! Have seen 70" tired buggys just swallowed up, don't go in there...

 

SERIOUS!

 

When I put it in 4wd hi the TRAC is on. Hitting the VSC button while in 4hi will turn TRAC off.

 

Allright, I went out and was able to test this out myself for a short minute today. I seen seem teens that had gotten stuck in an older Malibu and ran it hot trying to get out. They were in the back undeveloped area of a new subdivision where a street WILL BE one day, but for now its dirt, and it rained and they got stuck. I offered to pull em out and they accepted, they were happy to see me really LOL. I told them that I was not responsible for any damage to their car and the driver hooked up the strap himself. I hooked up and started pulling this car in 4H, with no buttons pushed or anything, it was doing pretty ok untill the idiot steering the car went right into the deep ass ditch like rut that was right beside us. We came to a stop, I poured the gas to the Taco trying to get her to pull on through. All of a sudden, the engine cut power and no matter if I eased onto the gas or floored it, the engine was still losing RPMs. I had to let off and ease back onto the throttle and I could feel the wheels turning but we were not moving. The engine cut power again, and since I had to let off for it to kinda "reset", I went ahead and switched into 4L locked the rear and had ATRAC on. Now in this mode, I was able to pull the car like 5 more feet while giving er hell and letting ATRAC do its thing. In the end though the car completly high centered and I COULD have pulled farther if I wasnt afraid to give it a decent yank. It wasnt because of my truck or my gear that I was afraid off, it was the ignorant ass 16 y/o kid that had already stuck his car THEN steered it into the ditch after he got help. I didnt want to give it too much and have him take out the back bumper of my truck. Anyway, I gave him a really gentle yank, and broke something off his car, I think he hooked on to a bumper cover support. By this time I was like I need to GTFO of here, this guy is an idiot. LOL He said he was gonna call his dad that owns a tow truck to get him out, I wished him luck and high tailed it out of there.

So yeah, like the OP says, I dont get why I got engine power cut in 4H with no button actions pushed. Im gonna have to investigate more on this.

 

bump for anyone that may have input on this

 

Sounds like they reverted back to the 2005-2008 4H default drive mode: Engine and brake regulation. Too bad you didn't do a short press of the VSC switch and another try in 4H to see what it did. I can only assume just brake regulation.

 

Hmmm Dont know if tranny heat would be the issue.

Is it possible to over heat the AT in like 45 secs to minute worth of pulling in 4H? Seems rather fast I think. The dirt was kinda hard pack with like 1 inch worth of soft sloppy mud on top of it. I wasnt digging in while pulling, really just spinning all 4 on top of the slick stuff. Though I WAS trying to go really slow since the kid was stearing backwards and the strap is kinda short (gotta get me a longer one).

 

Im thinkin I just need to do the locker mod turn all the nanny crap and trac stuff off, just shift into 4H lock the rear and give her hell. LOL

 

The idiot lights come on and the warning buzzer turns on if I remember correctly. I doubt anything overheated.

Edit: after a quick search:

 

OK thanks for confirming and letting me know Im not mistaking this for something else. If in 4H and I turn off TRAC, that leaves me with OPEN DIFFS front and rear right?

Is there a way to over ride the system and make it ALSD w/o cutting engine power?

 

Mine does not work quite like that. My settings work like this\
Start truck, all systems normal, 2H no buttons pushed
Hit VSC once brings up a light on the dash ALSD (this is still 2wd) hit again it goes off.
turn the dial to 4H, the green 4WD light comes on ONLY
in 4H I hit the VSC button again, I get the light TRAC OFF, once more on the button that same light goes away.
I push and HOLD that button in 4H, it brings up VSC OFF and TRAC OFF (this is open diff im sure)

Now, I have not figured out a way to get the ALSD to light up in 4H, I was under the impression that ALSD was the same thing as TRAC wich is the same thing as ATRAC. Please correct me if Im wrong. As far as I can tell the only way to get full engine power in 4WD is to push and HOLD the VSC button to turn everything off, but that leaves me with open diffs.

 

Been trying to tell you guys this, the is no unregulated TRAC in 4hi on my little '12 Sport. Have to turn everything off to get WFO throttle to the tires.

 

In all the years, ALSD has never lit up in 4WD.

Depending on what year you drive, you will get different names and functionality with the same hardware. ALSD, TRAC, ATRAC. Toyota loves their gimmicky names.

So we don't confuse your 2012 thread, I will leave the other years out. This is what I gather from your post where you tested the truck.

2012:

TRAC 2WD = brake and throttle regulation.
ALSD 2WD = brake regulation.
TRAC 4WD = brake and throttle regulation.
ATRAC 4WD Low = brake regulation.
VSC OFF TRAC OFF = no regulation.

 

The way I read that is like this;
4wd, no lights on: TRAC = LSD + engine regulation.
4wd, TRAC-OFF light on: ALSD + NO engine regulation.
4wd, TRAC-OFF light on, VSC-OFF light on: Open diff.

That would seem to fit with my theory.

 

OK, Fools rush in where angels ....

Like the OP, I have a 2012 4x4 SR5 AT V6. I do not have A-TRAC. I have read all the posts here, and am still confused, so I read the 2012 owner's manual, section 2-4 carefully, several times. Note that it only talks about turning A-LSD ON (and only in 2WD mode) and turning TRAC OFF.

Furthermore, it also says, " Automatic TRAC reactivation (AUTO LSD mode). With AUTO LSD mode, VSC OFF and AUTO LSD indicator lights turn on. The TRAC system will turn on when the vehicle speed increases." So, I'm not sure that A-LSD and TRAC are the same thing at all. See definitions below

Anyway, there are only 3 drive modes, and for me, only 3 VSC-switch modes, so the 9x9 matrix should be easy to understand, right?? From reading the manual, here's what I have:

...............................2WD-Hi................4WD-Hi.................4WD-Lo

Normal ....................VSC ON............... VSC ON.................VSC OFF
(After Engine.............A-LSD OFF............TRAC ON
Start).......................Eng Reg OFF......... Eng Reg ON

VSC-Button OFF..........VSC OFF...............VSC ON................VSC OFF
................................A-LSD ON .............TRAC OFF
...............................Eng Reg ON............Eng Reg OFF

VSC-Button OFF..........VSC OFF................VSC OFF................VSC OFF
Hold >3 Sec...............TRAC OFF...............TRAC OFF
.................................Eng Reg OFF..........Eng Reg OFF

Please help me fill this in correctly!

Here are the definitions from the 2012 owner's manual:

The active traction control system (A-TRAC) automatically helps prevent the spinning of 4 wheels when the vehicle is started or accelerated on slippery road surfaces.

The AUTO LSD system aids traction by using the traction control system to control engine performance and braking when one of the rear wheels begins to spin. The system should be used only when one of the rear wheels spinning occurs in a ditch or rough surface.

The system can be used on 2WD models and in 2WD mode on 4WD
models.

When the AUTO LSD system is turned on, the VSC system will turn
on automatically if vehicle speed increases.

VSC (Vehicle Stability Control) Helps the driver to control skidding when swerving suddenly or turning on slippery road surfaces.

TRAC (Traction Control) Helps to maintains drive power and prevent the drive wheels from spinning when starting the vehicle or accelerating on slippery roads.

Note: The manual seems to imply that in 4HI, if you push the VSC-OFF button once, TRAC goes OFF but VSC stays on, the opposite from what it implies in 2Hi where VSC goes OFF but A-LSD comes ON.

Whoever wrote this was on some good stuff!


N. Fowler

PS Post #32 in this thread has a pointer to the 2012 Owner's Manual sections 2-4.











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Good stuff here! As far as I can tell everything you posted is correct. Unfortunatley it looks like we are supposed to have engine regulation in 4H with no buttons pushed. I too read the owners manual and what I got from it was when it refers to ALSD, it says it prevents the REAR wheels from spinning. It doesnt say anything about using it in 4WD.

 

Either that, or it was translated using google translate with voice dictation from being hollered across the 2TR-FE engine factory in Japan with machines running in the background.

 

I think im gonna try somthin dumb. LOL

Im gonna go find a slick muddy spot and see if I can tie myself off to a big ass tree to pull off of. I will try each mode and get sombody on the outside of the truck helping me watch how the wheels spin (ill get em to record this crazy chit too LOL). Like this I should be able to try each 2WD & 4WD mode out and have a video reference to prove it. We might even be able to make a sticky out of it, cause we damn sure have enough threads on it.