Atrac question

A none 4runner guy told me that Atrac should be turned on before you're stuck, to keep momentum when you encounter an obstacle that might stick you.
Is this correct?
From what I researched, it seems to be something you turn on after you're stuck.
Can someone tell me the truth?
2022 Trail edition 5th gen

 

The none 4Runner guy is correct

 

In an effort of not sounding like too much of a douche, here's a video that can help explain some different features on your 4R.

https://www.youtube.com/watch?v=4uM-BiJPl2I

IMO, the only feature that should be used after you get stuck is a winch, shovel and/ or traction boards.
Most of the 4R's features are meant to keep you from getting stuck in the first place.

There are a couple videos that show crawl control getting a rig out of a sand trap... but I have never seen this work in person.

 

I pretty much always have it on when I'm in 4lo.

 

I agree with the previous posts. There is no reason to wait to engage traction aids, four-wheel drive, ATrac, etc.

It's harder to get unstuck from a stop than to carry a little momentum through terrain; even at very, very, slow speeds. An object at rest...an object in motion, as they say.

 

Depends on the terrain. On rocks and dirt, you can engage A-Trac as soon as you shift into 4lo. When you aren't losing traction, A-Trac stays in the background and doesn't intrude, so you can make sharp turns on the trail, etc.

In snow, deep mud, and sand, where you need wheelspin, keep A-Trac off, and use the locker only.

 

^^^^
Don't do this.

 

I leave it off until I visually see if I need it. You can overheat the system of it’s pulsing the brakes when it isn’t needed.

 

You must have never driven on sand dunes or in waist-deep snow.

 

@3JOH22A Sure have. There is a reason why they call lockers low-side finders. They ruin lateral stability off road/off camber.

 

Doesn't it only "pulse" when it's needed?

 

It watches for differences in wheelspeed. Some surfaces will cause that without actually getting you stuck.

 

This happens any time you're relying on wheelspin to move forward. The only difference is you're more likely to bog without the locker. Just need to pick your lines and be mindful of your surroundings.

 

^I speak from experience

 

^this is the perfect respectful argument for @Yotaholic to come mess with lol

 

I air down, switch to 4Lo, turn A-Trac on, and go. Haven't had any issues, and haven't gotten stuck even a single time all these months in a variety of terrains. Lockers are better, no doubt, but A-Trac is cooler. I have two lockers, don't use them and don't miss them. Use them once in a while not to lose them.


A-Trac

https://youtube.com/shorts/nnRvh1HQa8I?si=tUFvYk_towh4zfkN

https://youtu.be/VVmvm2Im9Is?feature=shared

https://youtu.be/B9XV1-oYKnQ?feature=shared

https://youtu.be/nAcZjXjYHrs?si=MW4Je1rLUNSSgFM0

 

Soon I will create a situation where the two rear wheels lose traction, one wheel in the air and one wheel in mud. With rear locker only you are toast. That's when A-Trac will lock the front wheels and get you out. In one of the above videos you can see the front locker alone is totally useless because a rear wheel also lost traction. A-Trac acted as two lockers and the truck walked right up.

 

I’m surprised you don’t use your lockers. Atrac is fine and all, but when your tires come off the ground crossaxle, there’s nothing nicer than pushing the rear locker switch and smoothly and instantly continue on your way. No fuss, no muss.

I could understand being more picky about when to use the front locker though.

 

^With A-Trac engaged you wouldn't even notice a tire in the air unless you look at the tire.

I typically have the rear locker engaged along with MTS on medium trails with rocks, dirt, and shallow mud. In deep snow, sand dunes, or deep mud I turn off MTS:

https://www.youtube.com/watch?v=Qk1AJg0GNp4

https://www.youtube.com/watch?v=8ZQt_KdyuJM

https://www.youtube.com/watch?v=ZdeD8DaNNKU

^The cameraman got a little too excited on the last one lol.

 

I may not have enough practice with A-trac…but mine doesn’t always react in the way in similar situations. Sometimes it’s a gentle pulse followed by “locker-like” traction, but other times it has to do a little song and dance before the computer decides what needs to happen to get traction. I wonder if maybe it’s smoother if you leave a-trac on all the time when off road? I usually try a-trac when I lose traction or think I’ll lose it soon.

 

Active Traction Control System is Toyota's "brand" for it's 4Runner On/Off-Road performance features. The A-TRAC functions include limited slip differential (LSD, front and rear), and locking differential (F-R LOKR ). My SR5 has selectable LSD front and rear open diffs in 2Hi, 4Hi. LSD is engaged by default in these drive modes. Switching to 4Lo disables all traction modes - TRAC OFF illuminated. To engage front and rear lockers, press the F-R LOKR button. A green ATRAC indicator is illuminated (should actually say "LOKD") and the TRAC OFF indicator disappears. This indicates that the front and rear lockers are engaged.

For those looking at the overhead panel switches on an SR5, the LSD button is the umm, car-squiggly lines-OFF button (tells me nothin'). The F-R LOKR button is labeled A-TRAC for some unknown reason. Again, it tells me nothin'.

BTW, anytime the TRAC OFF indicator is illuminated, you're running open diffs - rear open in 2Hi, front and rear open in 4Hi and 4Lo. When the TRAC OFF indicator is not present on the dash, LSD or F-R LOKR is engaged on the associated drive axle. Notice that TRAC OFF indicator remains illuminated when the mechanical rear diff is engaged. That means the front differential is OPEN. Numerous roller slip test videos and the 4Runner manual confirm this operation.

Lastly, the popular OPN video (post #3) shows John's 4Runner with a rear E-locker and front ARB locker climbing a rugged hill without any trouble. His brother, Steve, in another 4Runner makes the same climb using open diffs and the F-R LOKR. Nice driving, Steve. Pretty impressive that an electronic front/rear locker system achieved the same result as mechanical front/rear lockers.

 

Atrac does do not lock your differentials nor are 4runner differentials LS. Atrac applies the brake at whatever wheel is spinning. The application of the brake on the spinning wheel allows an equal amount of power to be transmitted by the differential to the opposite wheel. It is much like a LSD in that the brakes take the function of the internal clutches of an LSD. More brake effort, more power transferred.

 

This is a very odd post. You’ve confidently presented a lot of information as facts. But as far as I can tell, you seem to have entirely invented all of it. I’m curious where you got your information.

 

Thank you for the compliment. I've had a long career confidently presenting information as facts I stated that the 4Runner ATRAC system provides two main functions: limited slip differential and locking differential. This has been gleaned from a variety of credible sources:

• 2021 Tacoma and 4Runner manuals - Auto LSD System pp 301 and 302 respectively
• YouTube channels...
  • TFLoffroad - excellent off road performance on the Razor Rocks, precise roller slip tests confirming LSD and locker functionality
  • Driving Sports TV - good general vehicle reviews, valuable "how NOT to use traction control" tips
  • The Car Care Nut - great education on 4Runner mechanical systems
  • GX460 OFF-ROAD - brilliant dissertation on TRAC vs ATRAC functions while driving like a "bat outta hell."
  • Overland Pacific Northwest - awesome display of off road techniques in a 4Runner. These guys know what they're doin'

I suspect many folks here frequently visit these sources.​

Owners Manuals state that 3rd gen Tacomas and 5th gen 4Runners have Auto LSD systems. The GX460 OFF-ROAD cat does a brilliant job explaining the TRAC and ATRAC functions in terms of LSD and locker. TFLoffroad roller slip tests clearly demonstrate LSD functionality on the rear axle in H2 and the front/rear axles in H4. If you compare the 4Runner behavior with roller slip tests of a Toyota E-locker or a Detroit TrueTrac, vehicle performance is identical. The OPN video of post #3 clearly demonstrates identical behavior of mechanical front/rear lockers with "brake simulated" (i.e. programmable) front/rear lockers. I'm convinced that both 4Runners exhibited locked differential functionality.

Look at the 3rd gen Tacoma drive mode chart from Tacoma World. The Traction Control Braking/Differential column calls out:

1. Brake Simulated Limited Slip Differential
2. Brake Simulated Locked Differentials
3. Fully Open Differentials

I tested my SR5 on a typical desert hill near the Superstition Mountain, AZ. The Active Traction Control System is really a computer algorithm that manipulates the vehicles hardware. Together, the integration of software and hardware components creates the LSD/locking differential traction control system.

Made this hill in H2 and H4 open diffs, some wheel spin. Engaged LSD in H2 and H4. Drove up again, no spin at all. Forced some wheel spin
using left-foot braking to get the slip indicator to flash. This confirms (p. 303) that Auto LSD is engaged and controlling the slip.

 

BS on the ATRAC LSD and Locker post. ATRAC uses the antilock brake system to transfer torque to the wheel with traction by braking the spinning wheel. 5th gen 4Runners have open front and rear diffs with some models adding an E-Locker in the rear…

The post sounds like AI generated rant…

 

This is what I was thinking as well.

 

Yup…maybe we should keep asking it questions to see how far it can tie itself in a knot.

I don’t use chatbots, but I heard if you get two chatbots talking with each other, some pretty trippy responses start to come out.

Then again, the poster made a logical error by saying A-trac and lockers, and LSD are the same, because they have a similar effect. But I would think that even when a chatbots is making shit up, it would still be capable of maintaining logical consistency? At least you would think so. Hmmm, not sure now.

Maybe we should just ask it….

@Rgon_Amps : Are you an AI chatbot? Would you respond truthfully if you are? What is truth? Is truth good? Why or why not?

Also, if a bicycle and a skateboard both roll, does that mean a skateboard is a bicycle?

 

^Two chatbots talking to each other, with sufficient processing power behind them, will start inventing their own shorthand slang to improve efficiency. Happened at Facebook.

 

Happened at Skynet, in 2029.