How many seconds can a-trac work

[03_4x4Runner]

How many seconds can a-trac keep working? I was in some really rutted/washed out areas yesterday and the first section I went through fairly well. The left rear tired was carried in the air approx 10' going up a hill and I maintained forward motion. Several hundred feet later was another worse area. The back tire was in the air and one of the front tires was at times but the a-trac seemed to give up. It quit making the ticking noise and was just like open diffs. I eventually got through by going faster than I wanted to but I am confused why the a-trac did not put the brakes on on the tires in the air. I have videos but do not know how to post them. I tried this again today in another area and the same thing happened. Seems to work ok for a while then gives up. I know this is not a locker but it seems like it used to work better. I tried the downhill assist to test everything and it still works fine.

 

[cali_axela]

When was the last time you had your brake fluid flushed? ATRAC is hard on the brakes, and old brake fluid boils and becomes useless much faster than fresh fluid. So if it hasn't been flushed recently, that'd be the first thing I tried.

 

[eskim0chaos]

When was the last time you had your brake fluid flushed? ATRAC is hard on the brakes, and old brake fluid boils and becomes useless much faster than fresh fluid. So if it hasn't been flushed recently, that'd be the first thing I tried.

This, I remember reading it was around 6-12mins constant action. There is a warning before it completely fails because if it does you dont have brakes.

This is from land cruiser literature btw.

 

[03_4x4Runner]

I have flushed the brake fluid 3 times since new in 2003, last time was 11/09 so I should do it again.. It was nowhere near 6-12 minutes, more like 1 or 2. I wish I could post the video, it is kind of cool.

 

[cali_axela]

Try using nice brake fluid with a high boiling point, such as ATE Typ 200: ATE Type 200 Amber Brake Fluid -- it should retain better performance for a lot longer than most normal brake fluid, which degrades fairly rapidly.

 

[thirstyturtle]

I have flushed the brake fluid 3 times since new in 2003, last time was 11/09 so I should do it again.. It was nowhere near 6-12 minutes, more like 1 or 2. I wish I could post the video, it is kind of cool.

Please upload your video, I REALLY want to see it!

Go to Image hosting, free photo sharing & video sharing at Photobucket and you can make an account and upload them there, then at the very least post a link to them. Or there's always the old standby YouTube!

 

[12guns]

Come on w/ the video already!
There's not nearly enough youtube vids of our 4 gens out there...

 

[chaz]

atrac also doesnt work at high rpms, its best at around 2k. Understanding & Using ATRAC II+ - Toyota 120 Platforms Forum

 

[03_4x4Runner]

atrac also doesnt work at high rpms, its best at around 2k. Understanding & Using ATRAC II+ - Toyota 120 Platforms Forum

Thanks, that is some good information. I have my wife working on the video.

 

[Thai]

In the 2008-up Land Cruiser (current gen), ATRAC can work continuously for up to 12 minutes. Source: http://www.toyota-4runner.org/comparisons-reviews/56558-2008-up-toyota-land-cruiser-lx570-2.html

The 4runner's system is probably less robust than the Land Cruiser...so, anywhere less than 12 minutes i would assume. Still, what you described is odd. I would just get an ARB rear locker and be done with the guess work!

 

[midnight runner]

What's brake fluid got to do with this? Are the brakes w/ a-trac really getting that hot to the point where the fluid is boiling over? It takes a lot to get the brakes that hot.

 

[gm350reratliff]

How much time do you have to wait for A-Trac to start working again once you hit the 12 min time limit? I have wheeled the 4runner numerous times and have had the A-trac work without issue. I have some land in the Zuni mountains that can be a little rough getting into. The gate is 8 miles from the hiway on an unmaintained dirt road. On a good, dry day you can make it in about 30min from the hiway. However, I have had times where just getting out was a 5hour adventure. That was in a previous truck that was lifted, locked, riding on 35's and a lot of winching action but loaded down with firewood. I haven't wheeled the 4runner on that road yet because usually I have work to do out there and I just take the truck but I would like to know that it could make it without the A-trac quitting on me and leaving me stranded. That goes for any trail I encounter. I know there are some hard core wheelers on here, any hardcore wheelers have issues with this system? Maybe I do have a reason now to get a locker for the 4runner.

 

[klennop]

My thought after watching the videos is you were not giving the ATRAC enough time to do what it is supposed to do. It looked like you let the tires spin for maybe 1 or 2 seconds. Then you either stopped or reversed to go faster at the obstacle. For ATRAC to work it has to sense the wheels spinning so maybe keep the gas steady for a little longer next time. This may give it more time to work.

 

[DocMT]

My thought after watching the videos is you were not giving the ATRAC enough time to do what it is supposed to do. It looked like you let the tires spin for maybe 1 or 2 seconds. Then you either stopped or reversed to go faster at the obstacle. For ATRAC to work it has to sense the wheels spinning so maybe keep the gas steady for a little longer next time. This may give it more time to work.

I agree. ATRAC isn't always lightening fast to active/respond when a wheel or two is up in the air. Steady throttle application is all it usually takes to get the ATRAC functioning and transfer the torque to the other side.

 

[JB.]

More agreement. I think you were a split second away from atrac grabbing.

 

[03_4x4Runner]

I posted the video on a new post because I did not know if I could make a video link correctly. http://www.toyota-4runner.org/4th-gen-t4rs/83068-trac-concerns-1st-attempt-video.html Sorry for the confusion. It is hard to see on the video from behind the 4runner but the wheels where spinning a fairly long time toward the end of the video and it did not even seem to make the normal clicking noise. The spinning tires did not seem to slow down at all. I attempted this 4 times with the same results. Eventually I got a faster run and it and got through. It may be that this 4runner is 8 years old and does not work as good as it once did. Is there anyway a moderator can combine the post?

 

[klennop]

I am not doubting what you are saying, but from what I see in the video just give it a little more time with the steady throttle to see if it is the system or not. Or heck, show us some more video. Sorry I can't help more but it really seemed like you just gave up a little too soon.

 

[JB.]

It is hard to see on the video from behind the 4runner but the wheels where spinning a fairly long time toward the end of the video and it did not even seem to make the normal clicking noise. The spinning tires did not seem to slow down at all. I attempted this 4 times with the same results. Eventually I got a faster run and it and got through.

There's supposed to be an intermittent buzzer if brake actuator temperature gets close to shutting down ATRAC. If the buzzer goes constant for a few seconds, the system will shut down until it cools off and would be accompanied by the VSC light coming on.

If there's an in between state where atrac diminishes but the buzzer doesn't sound, I'm unaware of it.

Maybe the buzzer is not working properly. If you waited a few minutes before using DAC, perhaps the system was operable again at that point.

 

[03_4x4Runner]

No buzzer went off. I am going to try it on a rutted hill near me that I climb a lot and know how it atrac worked in the past to test it out when I get a chance. I did not try the dac right away after this but after I got home.