Does downhill assist really do this?

[TeryT]

I found this over on the RV.net forum. I had never heard of this - is it true?

The 4Runner on the other hand comes with a 5 speed automatic with Downhill Assist control that when engaged acts like the tow/haul mode on the Allison transmission on GM HD trucks. It will downshift a gear everytime you brake to allow grade braking so you don't fry the brakes. And you can also shift the lever to any gear you want, there's D, 4, 3, 2, L which helps a ton when coming down steep grades with and without the trailer.

 

[Fourty-four]

Not exactly.

I played with mine a few times, and it seems to basically crawl down a slope. You might be able to manually select the gear though..... I don't really remember.

 

[TeryT]

I've used it while offroading, but the quote sounded like you could use it as an engine brake while traveling highway speeds.

 

[mainer]

doesn't the book say that it only works in low range under 15mph. I've yet to get mine to work.

 

[Fourty-four]

doesn't the book say that it only works in low range under 15mph. I've yet to get mine to work.

Why doesn't it work? You just have to enable it under the right circumstances.

 

[JB.]

I found this over on the RV.net forum. I had never heard of this - is it true?

He's just using the wrong term. DAC works only in low range. He must be referring to the shift into 4th from 5th when touching the brake downhill in high range.

 

[JB.]

doesn't the book say that it only works in low range under 15mph. I've yet to get mine to work.

Low range, foot off the pedals, 15mph or less...it should work.
It'll temporarily disengage under pedal use and then come on again
when you take your foot off.

 

[TeryT]

Why doesn't it work? You just have to enable it under the right circumstances.

That must be it! I thought I was missing something when towing, going downhill & manually downshifting.

Didn't want to be caught doing the "old school" way if there was a new one!

As said, I have used the downhill assist offroading (in 4-low), and it works well - you just have to get used to it doing the job (and the noise it makes).

 

[mainer]

I tried it on a long down hill covered in snow. I was under 15 and had my foot off brake and gas. low range and hit the button, it did nothing. I'll have to try it again.

Doesn't the trany down shift when you apply the brake?

and is the trany in the sport a 4 or a 5 speed.

Thanks Cooper

 

[Bluto]

Re: Re: Does downhill assist really do this?

The 4Runner does not have anything like tow/haul mode.

They need to read up on Downhill Assist.

 

[TeryT]

Somebody else said: "This is what the Tundra has (not restricted to 4-low)- I'd assumed they'd just passed it over to the 4-runner. There is no engaging or disengaging it however. Simply, when you are on a downgrade with the brakes applied, the Tundra will down shift. "

 

[TeryT]

The person that made the post over on RV.net replied and said:

It works in 4hi for me, I just tried it today. I was coming down a steep grade and turned on DAC, tapped the brakes and the tranny downshifted a gear and increased RPM's which slowed down the truck. I don't know if that is a feature in the 05 and up models or if its in all of them. In 4Lo the DAC uses the ABS system to keep the 4Runner pointed in the direction you want down a steep hill under 15mph. The DAC works very well when towing.

 

[spyne]

I tried it on a long down hill covered in snow. I was under 15 and had my foot off brake and gas. low range and hit the button, it did nothing. I'll have to try it again.

Make sure you don't have your foot on either the brake or the gas when you acivate DAC. Reading through the manual it sounds like pressing either one will deactivate the system.

I've used mine a couple of times and have to say it's kind of creepy at first, plus it makes a bunch of noise as it activates and releases the brakes. Sounds like something must be getting ready to come loose under the truck.

 

[JB.]

The person that made the post over on RV.net replied and said:

It works in 4hi for me...turned on DAC...tapped the brakes and the tranny downshifted a gear



That would have happened whether he pushed the DAC button or not.

 

[Northof49]

It works in 4hi for me...turned on DAC...tapped the brakes and the tranny downshifted a gear



That would have happened whether he pushed the DAC button or not.

Exactly.....totally seperate features.

 

[AlphaQup]

Don't mean to stray OT but, does DAC work in 2WD mode? Tried it a couple times, but never worked for me. Maybe I just needed to switch to 4x4 mode?

 

[JB.]

Don't mean to stray OT but, does DAC work in 2WD mode? Tried it a couple times, but never worked for me. Maybe I just needed to switch to 4x4 mode?

Yeah, works in 4low only.

 

[Koz]

I found this over on the RV.net forum. I had never heard of this - is it true?

quote:
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The 4Runner on the other hand comes with a 5 speed automatic with Downhill Assist control that when engaged acts like the tow/haul mode on the Allison transmission on GM HD trucks. It will downshift a gear everytime you brake to allow grade braking so you don't fry the brakes. And you can also shift the lever to any gear you want, there's D, 4, 3, 2, L which helps a ton when coming down steep grades with and without the trailer.

--------------------------------------------------------------------------------

The Downhill Assist has nothing to do with the downshift grade braking, but yes the 4Runner has both.

The Downhill Assist work by using the low range (on the transfer case) and hitting the Downhill Assist button. The downshift grade braking is part of the transmission