A-TRAC/TRAC/AUTO LSD Explained (Easy to understand, I hope!)

Did we get bored with the Tacoma discussion and had to switch to Tundras?

 

poop...

I have seen a certain mod on here wheel the piss out of his open/open Tundra on many occasions

 

all of it?

not that it matters because we both hit the same tree

 

So let me get this straight.

In a 4x4 TRD sport without ATRAC, L4 is almost useless, unless you wanna spin tires.

So say if I was driving in mud, I'm better off driving in H4 with AUTO LSD (1 short press of button) enabled. That would be the 4x4 TRD Sport's maximum traction mode?

 

In a nutshell, what you are saying is right (I wouldn't use the word useless). Try both. 4H might get you a bit more traction, but 4L will get you more torque.

Quick correction, in H4 your traction control is TRAC (not AutoLSD). It is on by default. You press the button for a few seconds to shut it off.

If you want TRAC in L4 read this thread: http://www.tacomaworld.com/forum/technical-chat/51946-4low-trac.html

 

No... not almost useless. 4WD is still double the traction of 2WD. Open differentials apply power to the tire that can spin the easiest on each axle. Naturally, that doesn't help in most off road conditions... but having two axles with power is twice as good as just one.

I guess you also didn't read the first page (or other pages in other threads) where I (and others) have tried to clearly explain the drive modes?

HERE:

AUTO LSD is a 2WD (only) mode that works by pushing the button in 2WD. It is traction control (limited slip) without any engine output regulation. Normally in 2WD, the traction control has regulated output of engine power.

In 4WD-HI, the Tacoma goes into traction control without any engine output regulation, without touching any button. Toyota calls it TRAC in H4, but it is the same as AUTO LSD (except on all 4 tires).

In H4, the only change you can make is to turn off TRAC by stopping and pressing down the button for a few seconds... giving you open differentials (if you want free spinning).

The Yellow Wire Mod (4-low-trac-mod) fools the system to give you TRAC in 4-LOW... Greatly improving the traction in low range. Off Road 4WDs have A-TRAC, which is an even stronger Low Range limited slip, very close to lockers on the front and back differentials.

Hope that helps!

 

Ah I see what your saying. Ive read like 10 pages of this thread about 3 months ago to try to understand the differences. Now, after I got my Tacoma, I read it again to try to understand what I got. Ive read the pages, but its probably information overload. Lol... And Like you've said, the manual doesnt tell you anything! Lol thanks though David! I really appreciate you addressing my question directly.

Aloha!!

 

I am glad it helped! Enjoy your Tacoma... and keep on 4 wheeling!


A reminder:

*In nearly all cases, the standard mode in H2 and H4 will work the best for typical driving in those 2WD and 4WD conditions.

*If 2WD only, you have difficulty getting started because of snow, steep boat ramp or ice, try AUTO LSD. 2WD OFF ROAD TRD Tacomas have a rear locking differential which will provide more traction.

This is an information post to descibe the drive modes and how and when to use them. If your Tacoma is not a 2009 or newer, the information may not apply as some traction controls were options on 2005-2008 Tacomas and may operate differently than the 2009 and newer Tacomas.

This information is designed to assist in using the factory installed systems and in no way is meant to imply that after-market or non-Toyota products are either good or bad.



H2= 2WD High Range, H4= 4WD High Range, L4= 4WD Low Range

VSC is Vehicle Stability Control (keeps vehicle going where intended)

TRAC in H2 is a limited slip system that regulates engine output.

AUTO LSD in H2 is a limited slip system that doesn't regulate engine output.

TRAC in H4 is a limited slip system that doesn't regulate engine output.

A-TRAC in L4 is a system that equalizes torque across the front and rear axles to keep the truck moving over severe off road surfaces or lack of surface (with only one tire of four on solid ground, A-TRAC can move the vehicle). Some slipping occurs to allow steering and adjust to the surface traction needs.

REAR LOCKING DIFFERENTIAL is available to equalize the torque across the rear axle with no slipping of the rear tires. Steering can be affected, so Toyota recommends use for emergency (stuck) situations.


UP TO NINE DRIVE MODES

1) Normal street driving: H2 TRAC ON and VSC is on.
2) Slippery conditions, to get moving from a stuck: H2 AUTO LSD ON (VSC is off under 30 mph). Press VSC button once while moving or stopped.
3) Spinning tires prefered: H2 VSC OFF/ TRAC OFF. Press and hold down VSC button 3+ seconds, while stopped.

4) Loose dirt, sand, snow: H4 TRAC ON and VSC is on.
5) Spinning tires prefered, off pavement: H4 VSC OFF/ TRAC OFF. Press and hold down VSC button 3+ seconds, while stopped.

6) Spinning tires prefered with low gearing torque: L4 (with A-TRAC off)
7) Steep grades, large rocks, deep mud, severe traction conditions: L4 with A-TRAC ON. Press A-TRAC button once.
8) Spinning tires in front only: L4 with REAR DIFFERENTIAL LOCKED.
9) L4 REAR LOCKED and A-TRAC ON. A-TRAC comes on automatically when speed drops to under 3 mph to provide front traction to get you going, again.

ALL Tacomas have 1-3. ALL 4WD Tacomas have 1-6. ONLY 4WD OFF ROAD TRD Tacomas have 1-9.



*4WD High, the normal mode is TRAC (but is like AUTO LSD in that no engine output regulation occurs for a strong limited slip for off road conditions).

*4WD Low, I recommend those with the Off Road TRD package to press A-TRAC for the most traction control. All other 4WD Tacomas may find H4 TRAC will out-climb L4 (without any traction control)... That was my findings.

 

I've read about 25 pages of this entire thread so please forgive me if I skipped the one that might've answered my question...but is it possible to add A-TRAC to my 2012 TRD Sport DCLB 4x4 Tacoma?

 

Not really, since the A-TRAC device is powered by a hydraulic brake booster, and only the Off Road 4WDs have that. All other Tacomas have a vacuum brake booster. I am not sure if the spin sensors are different, but obviously there is electronics that are different.

As Whippersnapper said, your only option to have ultimate traction is to add lockers (only the Off Road TRD has a rear locker). However, what he didn't mention is that you do have a better traction option that is already built in to your Sport TRD and is FREE: It is called the '4-low-trac mod' (or the 'yellow wire mod')! It provides the limited slip of TRAC that you already have in high range, and allows it to work in low range.

Hope that helps!
David

 

Lots of great information and I thought I understood until I just went out & played around with my 2012. I thought I only had one option in H4, to hold for 3 seconds and shut off both Trac & VSC. I can push once and shut off Trac OR hold for 3 seconds and shut off both Trac & VSC. I'm confused now on what I get in each mode... can someone help?

 

Push & let go = Trac off
Push & hold = Trac off & vsc off

 

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. . . I now have my first 4x4 Tacoma ... ... so maybe I need to learn this stuff ... ...
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