Weird Incident-Input Appreciated

So, I have a 2016 V6 4X4 SR5 that I have driven without incident for about one month/1100 miles. It now has 16k total miles on it.

And then today something kind of strange happened. I was driving down a hill at somewhere just south of 50 mph. I was braking lightly to avoid picking up any more speed, and all of a sudden my RPMs shot up to around 3500.

At no point did I not have control of the vehicle. And it was not some kind of attempt by the engine at unprompted acceleration. What this felt much like is when I used to engine brake my old manual transmission Jeep.

It lasted for maybe 6-7 seconds when the RPMs fell back into their more normal 1000-2000 range, the briefly recurred again at the bottom of the hill.

The rest of the trip home was fine.

Has anyone ever experienced something like this with a Gen 3 Taco?

Thanks in advance.

 

Auto or manual tranny?

 

Yes. I was driving downhill, fresh new Taco with little miles, and the same thing happened to me. I think you can google it, I forgot what it was. I'm nearing 7k miles but it's never happened again.

 

Did you have it shifted into sport mode?

 

Had to be an automatic getting lost in shifting right? Guessing a mt you wouldn't be here writing on tw...

 

Some more info?

https://www.tacomaworld.com/threads/high-revs-downhill-normal.408371/page-2

 

Good point, I should have said that: I have the auto.

 

Oh cool. Thank you. Don't know how the heck I missed this!

 

engine braking, the trucks downshift so you don't have to burn your brakes up.

 

Yep. Engine braking. Normal.

 

Surprised this is your first time experiencing it. Mine does it fairly regularly but maybe its how my tranmission "self programmed" to my driving style, ever since it was new I use S-mode daily, and constantly heading up and back from the local mountains, so maybe my truck figured out quickly I like engine braking and gives it to me in spades, almost everytime I'm going downhill.

From my experience it does this when you're accelerating without throttle input (if the hill is steep enough that you'll be gaining speed if you're not riding the brakes), the only way I've figured out how to "cancel" it if I'm purposely trying to gain throttle free speed is to be in S-mode with 6th gear selected then it waits for your to tell it to downshift.

 

As noted with the auto it's normal, had it been a manual it would have been something odd.

 

It's normal, the 2nd gen's do it also. If you will barely touch the gas it will upshift back to 5th.

 

Cool. Good to know!

 

Gents, thanks. I feel much better for your input. This is my first truck and my only other off-roadey type vehicle was a manual jeep. So this unprompted engine braking was kind of new to me.

 

You have an SR5, no need to designate which as that is an Auto only model.

 

No. Not at the time.

 

You know, I was thinking about it. I live in central NC. So there are hills, but they are sporadic compared with conditions, say, 50 miles west of me as you get into the Piedmont. And most of the hills involve kind of gradual grades (they are almost plateaus at the top as much as hills).

When this happened I was driving in Chatham County, NC in a pretty hilly little area. Its kind of this sporadic band of sharp little hills that runs from Chatham up through Chapel Hill and into northern Orange County. The grade where this happened might just be the steepest place I've taken the Taco so far.

 

That is definitely engine braking. My 4runner does this too, felt kinda odd at first, but I’ve gotten used to it. It just helps to save your brakes.