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

You are welcome... I am just repaying this forum for helping me after I got my 2010... Nice to have a serious TW member to help out.

 

This was posted in its own thread... but may be helpful here as it shows the dial, buttons and lights that are touched and light up for the various drive modes:

Recently some have posted that the truck was 'stuck' in '4WD' because the light was on or blinking... only to later learn it was just the differential lock switch pushed in! That light is below the 4WD light...

The lights are different... So, I just took some photos so we all can see. Let's go through the levels of traction activation and see what it all looks like:



Normal dial position for paved roads or where traction assistance of 4WD (four wheel drive) is not needed.



The lower switch, next to mirror controls (car with skid lines below) is the VSC OFF switch. This also activates AUTO LSD when in 2WD with a quick push. Auto LSD is traction control without the engine output regulated.



This is what comes on with AUTO LSD active. The VSC OFF light goes out above 30 mph.



If you stop the truck and hold down the VSC OFF switch for 3+ seconds, VSC and TRAC both turn off for open differential(s) in H2 or H4.



Go into H4 (4WD High Range) from 0-60 mph if you need more traction because of poor conditions or off highway needs.



This is the 4WD High Range indicator light... two differentials and 4 tires. TRAC in H4 has no engine regulation, the same as AUTO LSD in H2.



For more torque to power through deep snow or mud or to climb up or down steep grades, stop truck, put tranny into N (Neutral, not Park), and rotate dial to L4.



Low Range 4WD indicator light. VSC goes off in L4 and both differentails are open.



If your 4WD Tacoma is an '09 + Off Road TRD, you have 'Active Traction Control' (A-TRAC) that provides the 'brake-locking' of any non-traction (spinning) tires front or rear for tractor like crawling/ climbing. Gives traction control while in low range. Push this switch just once when in L4 and A-TRAC will activate when-ever needed to keep moving while in L4.



A-TRAC activated light.

REAR LOCKER:



As Toyota states, use only as a last resort and turn off when out of trouble.



While in L4 (for 4WD Tacomas), press the RR DIFF LOCK switch. (I engaged it twice today while stopped)



The Rear Differential Lock indicator is the x'ed rear differential image. If it doesn't engage, or if it is pressed while in H4 or H2 (for 4WD Tacomas) it will BLINK! Remember, when locked there is no differential action to allow the tires to rotate at different speeds, as needed when turning.

 

Hugely informative post David K, thank you. I was a bit confused by the explanation in my '10 Prerunner owners manual & your write up clarified it. Their safety first jargon kinda muddles the explanation of the system capabilities.

Now I'll need to spend some time on loose gravel to feel the difference between lsd light, auto-lsd (trac off), the open diff (trac & vsc off), so I know which works best if I happen to get stuck or need more traction next time I'm up in the hills.

Of course, most important is figuring out which setting will be best for doing the occasional powerslide on wet pavement & loong slides on loose gravel fireroads...

 

Glad you liked it... You will have fun playing with the truck... Basically, it will do great at the standard settings... but a quick push of the button will improve the power to the back end for when the standard TRAC isn't enough... and if you want unrestricted tire spin, then stop moving and hold the button down for a few seconds to turn off all the traction controls and VSC.

 

That's what I thought & thanks for reaffirming it. It'll be interesting to see (with trac & vsc off) at what speed the system turns VSC back on. It sounded like anything over 30mph & it kicks back in.

 

I haven't experimented with the VSC OFF MODE to that degree... In TRAC OFF (AUTO LSD ON), the VSC is off to 30 MPH, yes... In VSC OFF, it should stay off until you are about to wipe out your truck and the sensors will re-activate the VSC to 'stabilize' you!

 

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Great instructional info. and additional links too. Thanks for taking the time to post this info.

PS ... I would give you some "Rep Points" if I knew how to do it ...
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Thanks for that! How about a helicopter ride sometime!?

 

I feel bad about piling on, but I bought a 2011 Tacoma TRD Offroad a week ago and had some issues with the controls in snow and this thread made so much more sense than the manual that I finally understand the system. My dealer tried but it was clear he did not really get it. Thanks so much!

One of my main reasons for buying the model is that I spend 2 plus weeks each year on the sand in Frisco NC on the Outer Banks, fishing and off roading. Your tips on driving at Baja (where I used to off road) were really useful. I have mainly used Ford SUV's and pickups on the sand and am really
Looking forward to using the Toyota.

Again, Thanks!

T

 

Happy to assist! I actually used my rear locker and the A-TRAC together to pull a 2WD Ranger up a slimely/clay mud hill 2 days ago... It was a breeze and amazed me how effortless it was pulling him to the top. I also had brand new tires that worked awesome! Hankook Dynapro ATm's.

 

My 2010 Tacoma TRD Sport has the VSC Off switch, but not the Atrac switch. Does that mean I have NO LSD in 4wd?

I have gotten the truck where diagonal wheels are off the ground and couldn't move. Fortunately I was able to PUSH the truck out while my girlfriend drove.

The sticker that lists what comes with the truck says "Auto Limited Slip Diff", but the thing doesn't perform NEARLY as well as my Nissan Frontier with LSD.

the A-TRAC/TRAC/AUTO LSD post explains things pretty well, but I don't have the A-TRAC switch.

 

The OFF ROAD TRDs have a hydraulic brake booster which gives the needed power to enhance the limited slip action of TRAC in H4 and A-TRAC in L4. While you do have AUTO LSD in H2 and TRAC in H4, they may not have as much effect as we with OFF ROAD TRDs experience.

There is a 4-Lo TRAC mod to fool your SPORT into giving you Limited Slip (TRAC) in L4... and those that have say it works great!

I wonder why people buy a SPORT if they seek an off road driving truck? I think the sales staff fail to explain the OFF ROAD TRDs have a rear locking differential, A-TRAC and the hydraulic booster...?

 

dealers dont know anything. I was playing with my truck at the dealers and put it in 4lo to see how low it was since he didnt know the tcase gear ratio. when i left they called me and asked me to come back because they coudnt figure out how to get it back out of 4lo.

 

WOW. Thanks david. I got my 2011 trd off road 2 weeks ago. It wasn't until I read your write up that I realized what I had. I didn't know anything about the drive systems. The sales guy didn't tell me anything about its off road capabilities. Or about vsc and how it works. Glad I bought the off road even though I had no idea what I was buying.

 

Exactly why I bring it up when I think there is a chance somebody is reading a thread that would benefit from knowing!

I also did not know what I had (other than an Off Road with a rear locker, which I had 2 of before)... That is why I came to Tacoma World to find out, as the manual or salesmen just didn't do the system justice!

It is fun to have 9 drive modes to choose from... even though we will mostly always use only 3 or 4 of them (H2, H4, L4+A-TRAC, L4+ A-TRAC+RR Locker)... Sometimes I hit the AUTO LSD switch while in H2 during wet weather for fun or on dirt roads that don't really need 4WD.

Have fun with your new Toy!!

 

Incredibly informative post... I have owned my truck for a week and really thought I did a good job reading up on it before I bought it but now I feel like I knew nothing at all! They really do a poor job of explaining the a-trac all over the internet/dealership! Thanks for a great write up I feel alot more confident now in my trucks abilities!

 

Thank you!

I guess they are leaving that up to us owners of A-TRAC trucks (to brag about it)?

It sure hooked me after I actually used it the first time when I was in a stuck situation thinking there is no way but a pull out or a lot of digging and jacking up, after I accidentally backed my truck into a pair of deep ruts and high centered the back on the differential and spare tire, while pointed uphill on a steep grade.

The truck pulled itself out with maybe just one front tire on firm ground... Yup, it works!

 

Guys, I guess this does get somewhat confusing after awhile, and for the sake of sounding like an idiot I guess I must. If it is not too much trouble; I have a 2009 4X4 Sport Extra package, which only seems to state interior additives ect., I screwed up and should have joined before I bought one cause I certainly would have gotten the off-road ed. but didn't know.
Does my truck lack 4X4 balls? I have put the TRD induction system and pipes which I have found out was a bad move using the TRD stuff, 3" REVTEK and 285 tires...just saying. Is the truck worthy of getting some 4 wheeling accomplished? Haven't had any problems with mild running yet.

Thanks, and the site is awesome!!!great help.

 

I agree with Christian... your truck is fine... What you can do is the Yellow Wire Mod... also called the 4-Lo Trac Mod.

Your SPORT Taco has traction control in H4, but only open differentials in L4. This mod fools the truck into thinking it is in H4 when you are in low range. The result is limited slip in low range...

The next steps to take is get better traction tires... Dynapro ATM for all terrain and Dynapro MT for mud and snow... for example.