2012 SR5 Downhill Assistance noise - is it right?

RysiuM

RysiuM

New member
Hi guys, I have a question and maybe a problem - I don't know. This is the first time I ever used Downhill Assistance button. All by the book:
I set the drive for 4x4 Low, pressed DAC button and see the light on the dash came on. Started rolling slowly downhill - not even steep. The drive position was on 2. Not touching gas or brakes. The truck started rolling down until something started violent knocking noise during that time slip indicator flashed. All seems to be exactly by the book except the noise. Is it normal?

I had my traffic camera on ant it actually picked up the nature of the noise. here is the piece of the video with that part.

https://youtu.be/UIi8t7JpTSo

It seems to be only when the DAC activates, 4x4 Lo and Hi works flawles and quiet. I think DAC operates using brake pump but the noise is nothing like ABS or TAC I ever heard. The truck has 35k miles and still under the extended "platinum" bumper-to-bumper warranty. Should I see the mechanic about that?
 
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RysiuM said:
Hi guys, I have a question and maybe a problem - I don't know. This is the first time I ever used Downhill Assistance button. All by the book:
I set the drive for 4x4 Low, pressed DAC button and see the light on the dash came on. Started rolling slowly downhill - not even steep. The drive position was on 2. Not touching gas or brakes. The truck started rolling down until something started violent knocking noise during that time slip indicator flashed. All seems to be exactly by the book except the noise. Is it normal?

I had my traffic camera on ant it actually picked up the nature of the noise. here is the piece of the video with that part.

https://youtu.be/UIi8t7JpTSo

It seems to be only when the DAC activates, 4x4 Lo and Hi works flawles and quiet. I think DAC operates using brake pump but the noise is nothing like ABS or TAC I ever heard. The truck has 35k miles and still under the extended "platinum" bumper-to-bumper warranty. Should I see the mechanic about that?
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100% normal. Carry on.... :)
 
I use 4 Low and gear 1 or 2 for hill decent. DAC is too noisy and makes the passengers ask too many questions.
 
I have found it usefull twice. Most times 4Lo and 1st gear will do the job but when it is scary steep and you are on very loose scree it is a life saver.
 
I was wondering the same thing about crawl control in my 2016 4runner, then read in the manual that it is normal for ABS to activate. I hate ABS, so haven't used crawl control sense then, lol.

Still though, seemed pretty weird since I was just trying it out on relatively flat ground. It was a bit sandy, but still seemed odd for ABS to kick in that much on flat ground. Was it really that hard to keep traction?
 
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ExploreABitMore said:
I was wondering the same thing about crawl control in my 2016 4runner, then read in the manual that it is normal for ABS to activate. I hate ABS, so haven't used crawl control sense then, lol.

Still though, seemed pretty weird since I was just trying it out on relatively flat ground. It was a bit sandy, but still seemed odd for ABS to kick in that much on flat ground. Was it really that hard to keep traction?
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The reason descent control and crawl control make such a ruckus is because they are trying really hard to keep you going slowly. Not so much of a traction issue, more of a speed issue. Especially on level ground when low range will easily get you going a couple of MPH faster than the control system wants. The systems have their purpose and it's good to try them out so you're not scared of them when/if you need them someday.
 
Noise

Thought I broke something when I did it the first time!!!! Hardly use it, didn't use it in Moab on Fins and Things, didn't miss it
 
mo_mo said:
The reason descent control and crawl control make such a ruckus is because they are trying really hard to keep you going slowly. Not so much of a traction issue, more of a speed issue. Especially on level ground when low range will easily get you going a couple of MPH faster than the control system wants. The systems have their purpose and it's good to try them out so you're not scared of them when/if you need them someday.
Click to expand...

Thanks for the clarification mo_mo, that makes sense. I'd definitely still like to try it out on a couple of actual downhills I was thinking it might come in handy for one day.
 
ExploreABitMore said:
I'd definitely still like to try it out on a couple of actual downhills I was thinking it might come in handy for one day.
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It makes too much racket unless you are going uphill. It's a bit of a gimmick, but can be handy for uphill allowing you to focus on the trail and terrain. I use mine on occasion.
 
BobsTrail said:
It makes too much racket unless you are going uphill. It's a bit of a gimmick, but can be handy for uphill allowing you to focus on the trail and terrain. I use mine on occasion.
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Thanks for the heads up. Sounds like I probably won't use it too often. Might be because I'm used to dirt-biking and focusing on terrain that is going by very fast, but I just don't see a big advantage to that. No problems (as of yet) focusing on trail/terrain and the pedals. I'd actually rather feel more in control and be able to use the pedals.

I did try out the multi-terrain knob next to the crawl control this weekend on a steep, rocky hill. That's supposed to help with traction, right? Either way, didn't feel my stock "highway" tires slip once. Felt like it was doing something good for me :)
 
FrontRange4Runner said:
100% normal. Carry on.... :)
Click to expand...

Thanks guys for your answers. I watched few youtube videos from other guys having the same sound while using DAC in 4Runner, Tacoma or LC. It is scary for the first time, as it sounds like trying to brake by switching to P. Anyway, I'm glad the truck is not broken, even it sounded like one. :reddance:
 
BobsTrail said:
It makes too much racket unless you are going uphill. It's a bit of a gimmick, but can be handy for uphill allowing you to focus on the trail and terrain. I use mine on occasion.
Click to expand...

I completely agree with this assessment...great for uphill; annoying for down hill (I probably haven't been in a situation that truly required it).
 
RysiuM said:
So can this DAC be used for crawl control or "crawl control " is some different button?
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Not sure, but I think they are fairly similar. Maybe the difference is crawl control can also be used uphill? I was under the impression I don't have DAC because it would be redundant with crawl control. Hopefully, somebody more knowledgeable can answer this

Guess we at least know they're similar as far as all the annoying, strange noises they make lol
 
RysiuM said:
So can this DAC be used for crawl control or "crawl control " is some different button?
Click to expand...


They are two different things. DAC only works going downhill hence the name. I believe it also works in reverse if you fail a hill climb or you just prefer hitting the trails backwards.
 
So much uneducated information in this thread that is misleading, or just plain wrong. It's just going to confuse new people even more. [MENTION=66316]1engineer[/MENTION].:dizzy:

Harper7 explained DAC and HAC best with these videos: CLICK HERE

Crawl Control is an expanded version of these systems.
 
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