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

The traction control works via the brakes. It applies the brakes to the spinning wheel to give the power to the non spinning wheel.

 

Right. So that happens in both 1 and 2?
Lol I really don't get the difference between those 2

 

1 - light traction control
2 - heavy traction control

 

Ok so 2 uses the lsd to get the heavy traction?

 

it doesn't really occur in the differential even though they call it that. the brakes are what controls it.

 

Good... I think drwx is explaining it fine. Here is my possible edit:
1) TRAC = Light traction control (uses engine regulation or "throttle cut" and the brakes)
2) TRAC OFF & AUTO LSD = Heavy traction control (no throttle cut, brakes the spinning tire only)

 

Hey guys, I've got a 2015 SR5 4WD. I don't have an a-trac button, but I do have the "RSCA OFF" and the traction control off buttons to the left of my steering wheel. Is my truck straight open diffs or is there a secret mode that can help me that I'm not aware of?

I'm asking because I'm trying to decide if installing an after market true LSD would be worth it.

Thanks!

 

When you are in 4H you automatically have electronic limited slip both front and back. This gives you amazing traction. When in 4L you have open axles but there is a simple mod you can do so that if you want you can have front/rear limited slip in 4L.
The RSCA if for your side air bags. Read your manual for information on that.

 

What's the simple mod?

 

A-TRAC and MTS are only available on 4WD Off Road Tacoma's.
The mod mentioned tricks the truck when in L4, to think it is in H4 with traction control on. Search 4 Lo Trac Mod.

 

Thank you David k for this carv informative thread. I recently purchased a 2009 TRD off-road and this really helps me understand what the owners manual failed to properly explain. So far I haven't gotten out to try this out off-road but in January in Montana a drive to work is an adventure.

I look forward to using this system in the mountains soon.

 

That is super! Your '09 and my '10 have the same operating features so if you have any questions I am happy to advise. Have fun and maybe you will be able to do better snow testing than I could here in San Diego County... where we do get snow, above 4,000', maybe 6"-12" deep, for a few days, each winter! LOL.

I found A-TRAC with the locker on was better in snow, if you need low range. The locker on prevents the engine cut (over 3 mph) but when you come to a near-stop or stuck, the A-TRAC makes the front wheels have locker-like traction to help you crawl out of the stuck.

In 2012, Toyota added the TRAC OFF (button push in H4) feature whereas our Tacomas (2009-2011) are already in the stronger 'TRAC OFF' mode when we go into H4 (no button push). I sure don't know why they made H4 the same as H2 with an engine-regulated TRAC, but maybe it was less confusing to have TRAC be the same in 2WD and 4WD-HI, then have you press the button for the stronger 'AUTO LSD' in H2 and stronger (but poorly named) 'TRAC OFF' in H4.

 

Took it out some today not anything serious. There is 6-8 inches of dense warm snow. For those that don't live with snow regularly warm snow is most slippery could snow actually has a fair share of grip. I put it in 4L turned off a-track and got it in a position that pip unequal traction on the wheels so it would not climb. Tried a-track to get out and we'll wt moved forward some with some wheel turning but only a few more feet.
Remember warm snow so one you spin you polish the snow and reduce grip by a great deal. I then locked the rear with a-track on and gained some more but the trottle cut out prevents any real gain still slick snow is still a problem. Then I turned off a-track backed up ans made a short run and was able to to make it. In all fairness I never backed up and gave a-track a chance with any momentum.

I'm an experienced driver in show both on and off road. I have several 4×4 trucks. This is going to be interesting learning how to best use the features my Tacoma has in different scenarios.

I've read some comments as to why you would ever want open diffentials. I have at least one reason that having open diffentials is better than any locked or limited slip diff. Side hilling in snow. What happens is when you spin both tires on an axle you loose side bite. Then gravity takes over and you will drift down hill. That's all fine until you hit a tree or drop off a cliff. So the ability to turn off these things is very important.
Sometimes you just have to add traction with some chains to continue. But once stopped or in a position that traction is uneven you can always turn it on to get moving again.

 

Perfect!

 

Another good test of my a-track in snow today. This was awesome. We went ice fishing a friend hooked us up with some private property access to the lake. It had a steep driveway that was unplowed.

The first truck a Chevy Z71 off road attempted to climb out failed on 3 tries. I have chains in my truck so I moved past to get out so if needed I could chain up and tow everyone out .

I put it in 4L a-track on locked up the rear climbed out no prob. The next a Nissan tried and failed to climb out. I got my strap out and went back down. Hooked up and pulled him out . The Chevy tried and failed again. I went down again. Hooked up to him and started pulling. Made it halfway and stalled out. I figured I'd have to chain up the Chevy was heavier than the Nissan.

I picked up the throttle to about 3000 rpms and all of sudden we started moving all the way out.

This was awesome I'll post video if my friend sends it to me.

This little truck is pretty amazing.

 

Oh, what a feeling!
Toyota + A-TRAC!

 

https://youtu.be/y3JwFTee7i0

 

So what's with Toyota's summary for the 2020? Off-Road does not include Auto LSD or A-TRAC.... Pro is left out on A-TRAC... Also appears to have added a new term 4WDemand? FYI I'm just learning about this stuff as I'm trying to decide on buying a SR5 or OR (new to 4WD and Tacomas). This chart totally threw me off...

 

That chart also makes no sense to me. Hope someone can clarify.

 

My respects and salute to the great David K as he has done a outstanding job, with unlimited patience for the past 10 years trying to document these features. From his books to TV specials, David always keeps his professionalism and respect for others which is rare and appreciated.


Personally, as a impatient BS’er, I would be happy to explain any of these questions, as I speak with the easy assuredness of the unconsciously ignorant.