A-TRAC Videos (Active Traction Control in Action)

Makes me glad I have one!

 

+1...for when I finally get the truck off the black top.

 

Great videos!!! Thanks for the information

 

Atrac is great. It really slows you down though in low traction conditions=not great for mud, but great in rocks and rut crossing. I've used it in some frozen-hard snow and it worked so well I turned it off because it was no fun!

 

Odds are poor Not that your truck isn't awesome...but, you know...everyone ends up wubbing their truck because it's theirs.

 

Only if that locker comes with A-TRAC

Lift coming soonish by the way...next 2 to 3 months...doin my research right now...

 

So when in slick mud, water, you turn off VSC and give her some gas in 4 HI? Or do you just leave the TRAC and go 4 HI?

 

Turning off the VSC (H4) is putting you in standard old 4WD with open differentials... ie. one tire in front and one in the rear getting torque... and it is the ones with less traction, so they spin. In L4, the VSC is off... and before A-TRAC all you had was an open front diff. While I don't have any serious mud driving yet in my new truck, I can tell you that deep sand is easy stuff with TRAC in H4 (VSC ON).

This thread is on A-TRAC which is enhanced LSD in L4... and as you can see by the latest video Crom posted, is just like having lockers...

 

Awesome post! Best off road tech post yet. +rep
I used ATRAC in the mud recently. It did not overheat the brakes, and this was 3rd gear revving out, axle deep sandy mud. The locker is good too, but this shuts off ATRAC above crawl speed. The comment that ATRAC is no good in mud are wrong. As I begin to get stuck in mud, usually one or 2 tires still have grip, and usually on the same side. ATRAC would only kick in hard, when needed. I didn't find it cycling on nearly as much as one would expect. In a mechanical LSD, friction of the clutch packs eats sup some power and generates heat as well. Only a mechanical locker is without these losses.

 

Here are mine...

http://www.youtube.com/watch?v=kdcXxBIm6KQ

Why you want to keep the RPM's low, to much and ATRAC could kick in and blow your diff. Listen to the "bang", any more deflection in the front differential I'm sure it would of blown. Not sure if the taco's are 2 pin or 4 pinion front diffs... if they are 2 pin be careful out there.

Atrac stopping my wheel quite abruptly...
http://www.youtube.com/watch?v=Ai0gMBklXGA&feature=channel

 

Sorry to say 2000uzj, but my A-TRAC (and all other A-TRAC videos I have seen, mostly FJ Cruisers) do not do what your Land Cruiser is doing. A-TRAC uses the brakes, not gears to match tire rotation on both sides... In your videos I see free spinning of the loose tire... that is not A-TRAC working... maybe TRAC, but not A-TRAC.

There would be no damage, because it doesn't suddenly engage, like your video showed (not sudden kick in)... it works from 1-30 mph... The reason it wouldn't damage is it is the same as stepping on the brakes to stop, which doesn't damage drivetrain parts.

I suggest taking the L/C into Toyota and see what is wrong!

 

No, I didn't mean A-TRAC uses the gears transfer power. It does use the brakes (you are correct). It applies the brake to the wheel with less traction and transfers power to the wheel with traction. ATRAC in the video is working, but when it grabs the brakes (what the video was showing) and the front wheels are spinning it will stop them abruptly. The 100 Series Cruisers have 1st gen. atrac, they never received 2nd gen. or 3rd gen. software. It's their nature. I have worked ATRAC to death and experimented in every way possible in every terrain and every off camber situation.

Reason I showed the video was to show you guys if ATRAC does not kick in immediately, which seems to be the 1st gen. problem, it can stop a fast rotating wheel and cause the front differential to flex (pinion gear), the pre-load on toyota differentials aren't that high. If you look on IH8MUD you will see that most guys that wheel there 100's with the 2 pin front diff end up blowing them. the 4 pin found in 2000+ are tougher, but CAN be blown. I wheeled with Koruptaco and gcwaterski last weekend and was watching it. It did not seem to really "grab", maybe I didn't catch it.

We all know what ATRAC does, its a great system and has its benefits over lockers. But it also has its downsides...

--- trac uses the thottle
--- ATRAC uses the brakes.

So your saying my ATRAC does not function properly? What the this video and let me know if you see the system grabbing upfront.

http://www.youtube.com/watch?v=SzHYlYLTjOg

EDIT: to add to my post, in that atrac video of me crossing the ditch, I was using almost no throttle, as I'm sure you know, ATRAC does not grab the brakes when idling. Right when you put your foot on the gas and the ECU receives input it will activate ATRAC. That is why my tires were spinning. Not trying to pick a argument, just wanted to clarify my statement above.

 

Just wanting to learn amigo... no problem here... but the new (Tacoma) A-TRAC does not even come close to allowing a tire to spin freely like that... Unless you pushed the A-TRAC button after your tire was spinning...? I think not...

Now the last YouTube you posted is more like what we have on Tacomas... a controlled locker action that keeps the two front tires (and rear tires) at matched rotation or pretty close to matched (I think 'IsThataHemi' said it was 5% difference).

I did not know there were 2 or more generations of A-TRAC... Seems they have greatly improved it since your model? The new TRAC is also perhaps much better, as it works very well in H4 at traction. In fact, I have climbed just as high on a mud hill in the desert in H4 (TRAC) as I did in L4 (A-TRAC). TRAC in deep sand is also greater by far than my earlier Tacomas performed. The 2010 Tacoma is like a completely different vehicle when it comes to four wheeling than my 2005 Tacoma! (A-TRAC became available on OR 4WD Tacomas in the 2009 year model).

Thanks for your time to share your A-TRAC videos and clarify the differences between your Land Cruiser and our Tacomas!

 

http://www.youtube.com/watch?v=UNyVGelEqlo
this is all atrac its hard to see on this version but on my good quality version you can see it slightly working the rear going up the hill. once the front tire leaves the ground at the top you can see it grabbing hard.

 

Here is a very good video of A-TRAC in action as well. If you listen very carefully you can hear the solenoids increasing hydraulic pressure to the passenger side front wheel at 21 seconds into the video, very near the end. I know because I have heard it before on my truck. (In my opening post video #5 @ 12 seconds)

http://www.youtube.com/watch?v=GVZLQp3s0EE&feature=related

Same video as above but in slow motion

http://www.youtube.com/watch?v=mV0NHk5W3JU&feature=related

 

Gen1 has 1 wheel speed sensor for ATRAC, GenII has 2 sensors (found in the 120) and so on with newer generations of this system. I'm not familiar with the new "crawl control" in the 200 series and new 4RNR's but I would think thats the best of the best in terms of electronic traction distribution.

If you have a wheel off the ground and let off the brake and gas and let it idle, will atrac let the wheel spin freely since there is no throttle input going to the ECU? Mine does that and it gets annoying because right you put your foot on the gas ATRAC kicks in and lurches forward. I'll take a detailed video of how gen1 ATRAC systems works in off camber situations soon. Just have to get some guys together to make a little clip of same obstacles and different ATRAC gens at work.


Video to follow in a few days...

Nick

 

Here is a very primitive video direct from Toyota corp. It's almost worthless except for the audio portion.

http://www.youtube.com/watch?v=A2eyBCX0ZWQ

 

Thank you for your video contributions and welcome to TW. I can tell that our A-TRAC in our 2nd gen Tacomas do not perform the same way as your specific Land Cruiser does at least according the the video you posted.

However did you see the Land Cruiser video I posted in post #21. It seems to work very much like our Tacomas do.

Also, I don't know the first thing about the Land Cruiser... But I can tell you for sure that our Tacoma trucks have only one wheel speed sensor.

 

hmmm, I'm not sure about this, but there could be one for ABS and the ECU and another for ATRAC? Because I have read somewhere that the different gens of ATRAC have more or less sensors for wheel slippage that contribute to a quicker/smoother response when a wheel looses traction. I'm not sure why Mr.T would put 2 speed sensors on the wheel, but apparently there is more than 1 sensor on the newer gens.

About the video I posted, I believe I was idling as the wheel came up, having no throttle input makes the wheel "idle" like it would on the ground, when it receives a signal from the ECU ( when my foot goes on the gas pedal), it senses me wanting to move forward, giving ATRAC the command to engage and make forward progress.

 

That looks to be the normal brakes stopping the wheels when they loose traction, ATRAC wouldn't stop a wheel going downhill, no throttle input. Plus the brakes cancel ATRAC... ask me how I know that