Automatic tranny downshifting

Hello, new to the forum, have a 2014 4.0 auto 4x4 and I've noticed it likes to downshift when riding the brakes going down hills (southern WV, there is no flat ground). Seems like it only does it at slower speeds (30-40 mph). Gets on my nerves sometimes, especially when just slowing down to the speed limit in town. Wondering if anyone else has noticed it or had issues with this?

 

That's how they are man.

 

I have experienced the same thing when hitting 40 on a particular hill on my way home from work. I just throw it in neutral and ride it out.

 

It's a intentional. Using the engine as a brake.

 

I figured it was designed that way, just annoys me. I've had it do it around 30 mph and it felt like I slammed the brakes on. Then it takes a while for it to shift back up. Only real issue I have with the truck.

 

Normal and beneficial

 

It is not an issue ... It is a feature.

 

ENGINE BREAKING and harsh downshifting . Is your transmission low on fluid ?
For you guys with higher mileage ....Read this http://www.sonnax.com/parts/1778
Page 33 and 34 of this PDF explains downshifting
http://www.toyotatundraforum.com/pdf/A750E.pdf
beleive it or not , your truck is designed to save fuel when coasting . When you take your foot off the gas , the PCM tells the injectors to turn off . This is why your truck feels like its slowing down in comparison to older vehicles you have owned . Combine this with the converter remaining locked up and the transmission downshifting while going down hills can really be felt in the drivers seat .

 

Mine also.I have had mine do it at 65,on cruise,going down a long hill;where my speed gained about 10 mph.I don't mind it,but sometimes,at about 30-35,I can't get it to "brake".Seams the longer you coast,and harder you brake,affects how/when it brakes.

 

If I could shut that feature off, I would. I agree with your assessment.

 

It could either be the AI Shift .. it operates when the truck is in D... if you're in a low enough speed, you could try putting the shifter in 4 and see if that helps.

Or the Brake Assist... which I guess you could put it into N (but not recommended)

 

I would love to disable but Toyota says that they can't do anything about it

 

Tap the gas

 

I was bothered by it at first, as I came from a standard I4. But I have since gotten used to it. When you know it is coming you can pull off the brakes as it downshifts and it can be pretty smooth.
Hopefully you get used to it.

 

Had to look up the details of the AI shift. Never heard of it before. The fact that it exists bothers me more than the action it does. Didn't do it at all during the test drive. If I can't figure out how to deal with it i might be looking for a 5 or 6 speed...

 

It bothers you that it is there to save you gas ?

 

Riding the brakes going down hills is dangerous when hauling a heavy load, since the brakes can overheat. Better to downshift and rely on engine braking. You also get better throttle response if you need to accelerate, since the engine is already at higher revs.

The Allison trannys in heavier trucks automatically downshift when you tap the brakes, for the same reason.

 

I agree that engine braking is the way to go, not only when hauling loads, but sometimes when going down a long or steep hill. I like to have control over that though. Being able to turn it on or off would be great. With this I don't have that option, at least I haven't figured it out yet. That is my main issue, that the transmission does what it "thinks" is best for the driving conditions, not what the driver thinks.

 

^That is the point of an automatic...

 

I don't get all the hate on this, IMHO it is a nice feature that I use every day. Near my office there is a short down grade that if you don't ride your brakes you will be 15+ over the speed limit at the bottom. (One guess where the cops put their radar trap ) A slight press on the brakes and presto I'm saving the brakes, gas and not getting a ticket. What's not to like about that?