Transmission Down-Shifting on it's own !!

I had this happen a couple of times, coasting down a incline at around 45mph. The transmission would down shift a couple of gears and motor would be reved to around 4000 rpm. I took it to the dealer for 15K service the next week, they checked it out , said no problems found. Well within a week it did it again, this time around the same speed but it down-shifted the instant I touch the brake to keep from exceeding the speed limit to much. I let it go just to see how or what it would do. Well it stayed at 4k rpm for a good 1/2 mile. I finally applied some power and it up shifted back to normal. So has anybody else ran into this un-needed and un-explained down-shifting.

2011 TRD V6 Tow Pkg

 

i’ll go ahead and ask auto or manuel thans?

edit: i’m going to assume it’s auto. and i have not had this happen.

 

I have no idea what it is doing, but just a though, i drop gears in my manual when going down hill to control my speed, could this have something to do with it?

I have never used the auto before, so i dont know

 

You have an auto so it does ALL it's shifting on it's own.

But the case you described doesn't seem right. Unless the auto's in the Tacoma like to do some serious engine braking.

 

is there a tranny reflash tsb for the 2011's?

 

My 09 does the exact same thing.

 

it is normal, especially on a new vehicle. there is a lot of talk on TW about it, it seems to be really noticeable on a new vehicle, I think that as something to do with the ecu learning your driving habits. I am almost to 30K and it either doesn't do it anymore or I don't notice it. I can't believe the tech at Toyota didnt know it was normal....

 

Downhill Assist control?

 

Yep my 2011 does it. I do a lot of mountain driving and kind of like it now. Just tap the brakes and the engine will shift to control your descent.

 

It's called engine braking , it's not a malfunction , is normal and beneficial

 

Yep, same here. Keeps me from having to ride my brakes.

 

Bingo.

And for reference purposes...

http://www.toyota.com.au/glossary

Fink

 

My '05 will drop down one gear on a decline when off the gas and I tap the brake. But never more than one gear.

 

not so beneficial if you want to coast, almost avoided toyota alltogether after renting a camry that did it really bad

 

Neutral?

Fink

 

You can't operate the DAC unless your in 4LO.

 

Gawd I'm sooooo glad I have a 6spd...

I can choose which gear the truck is in. Crazy!!!

 

Yep, I would call it the down-hill engine braking. I had tried the DAC but was only in 2wd so it did nothing. If it is the braking effect , then it works good. I stayed right at 40-45 all the way to the bottom, the only way it would return to norm was to apply a little engine power then it would shift up and continue. Regarding the 2 gear downshift, i just assumed it was since it went from 2200 rpm to 4000 when it downshifted. That is more than just dropping from OD, it dropped from OD and shifted down a gear. But bottom line is that it seems nothing is out of the ordinary per your guys posts.
Thanks,

 

My low milage 07 does the same thing. I was allittle worried at first. But seems like it helps on long decents, where I would normally manually shift in to lower gears to control speed.