RPMs Shooting Up on Random Downhills

I’ve noticed in my 2019 SR5 automatic 6 cylinder that occasionally when I hit the brakes going downhill, my rpm’s will jump to 3K or slightly higher and the engine revs loudly. Not every time - only sometimes.

I don’t have downhill assist and I’m not in S Mode, nor do I have ECT on. Just regular D. Most of these hills aren’t even that big or steep.

I guess my concern is that it does this intermittently. If it was built in engine braking, wouldn’t it do it every time/consistently? It just randomly does this. Anything to be concerned about? Or is this normal?

 

This is totally normal. I've noticed there isn't much rhyme or reason to the downshift and engine braking.

 

I think that’s the programming. It’s not like that Chevy Celebrity that just hung out in overdrive when you sailed down the hills from your younger years. Probably for the better anyways; these brake rotors warp easily and have on older Tacomas too, so a bit of engine braking ain’t the worst thing.

 

it depends on how the AI-Shift is feeling that day. too bad they don't let us customize the parameters in the menu.

 

Thankfully his name isn’t Hunter, Whitehead, Poole, or Kaminsky!

 

Normal, when I start cruising down a long steep winding hill with my truck in 6th gear, if I tap the brakes the truck automatically downshift's to 4th. This engine compression braking will bring the trucks speed more under control, so as not to ride the brakes all the time. Works well when towing a trailer. I sometimes wish my old tundra did it.

 

If you have Cruise Control on and if the truck senses an increase in speed on a downgrade, it will downshift to stay within some close proximity of your set speed, resulting in a jump in RPMs.
If you are braking to reduce speed your truck may also downshift to assist with braking.
I don't know if the SR trim has the Clinometer. This may have some bearing on the occurrence of a downshift.
In any case of the above situations, it's normal behavior.

 

It’s just odd because I go down the same hill(s) 5 to 7 times a week and it’ll only shoot up the RPMs maybe 1-2 times out of those trips. The inconsistency was what troubled me.

 

Mine is inconsistent. Depends on my truck's payload at times, i.e. another passenger or something in the bed. I suspect that even a tailwind will trigger the downshift with cruise control on.

 

Could be low on transmission fluid, hence why the sporadic hill shifts when fluid level changes.
Checking transmission fluid is not my strong area.

 

Idk, every time I go down these same hills, and tap the brake in the same area at roughly the same speed, my truck will downshift to 4th every time. I think if your speed, and braking habits are inconsistent, so will the transmission's downshifting.

 

Gotcha. I don’t use cruise control. Who knows…

 

Gosh. I hope not. Just bought it a month ago and it’s a certified Toyota so supposedly was gone over with a fine tooth comb. Has a good warranty at least.

 

These trucks have a mind of their own literally. The A.I can be moody some days my tacoma runs super smooth and feels peppy and other days it just feels sluggish like it doesn’t feel like being driven that day. Quirky ass vehicles. What your experiencing is normal mine does the same thing

 

I went from 1st gen to 3rd and 1st thing I noticed in winter was the truck takes over(ABS, Traction) on slick roads and it felt like I wasn't in control like with the 1st gen. I didn't like it and took some getting used to.

 

its normal
switch into s-mode and upshift is what I do sometimes
or hit the throttle will get you out of the hang up

 

They didn't check your transmission fluid level when certifying.

 

Definitely normal. I find it just depends on how hard I hit the brakes going down said hill. I found it occurring far more when I was in Colorado. I believe a light use or tap often triggered it more than firm presses on the brakes. I did it enough to feel natural when I was there. I'm sure it also has to factor in how quickly it detects you picking up speed with no throttle input combined with brake use. I've also driven other vehicles with this feature. A Jeep JL I drove in Maui comes to mind.

 

It does seem to happen mainly with the light tap of the brakes.
Yea - my previous vehicle (2019 Honda Fit automatic CTV) did engine braking on its own every single time going down a steep hill. So that’s what I was accustomed to. Not this inconsistency.

 

Hmmm. I’ll have to look into it. I don’t know if this is a sealed one. I know those are hard to check.