3rd gen - downshifts to 3rd on long downhills?

Hi guys - As the title indicates I'm getting downshifts from 6th to 3rd on long downhills without any driver input (i.e. solely coasting without braking, etc). The speed where this typically occurs is roughly 50 to 60 MPH.

I've seen remarks indicating this could be an engine breaking programming design, but I question this. I don't believe the vehicle should be making these kinds of decisions within these very common driving parameters.

Have others experienced this, under similar conditions?

Thanks for any ideas/suggestions etc.

 

I actually started noticing downshifting on declines AFTER the TSB.

 

It's part of the program. It's doing its own braking. In some situations its does it a little too aggressive.

 

That guys for quick information. I wasn't aware of the TSB.. It's going in for 5k service tomorrow so I'll discuss with the service writer.

While it's certainly not a big deal, I just feel the vehicle shouldn't be making decisions within these normal parameters.

If they apply an ECU flash update (or other electronic updates) I hope it doesn't make it worse or create other issues.

Thanks again..

 

So did you get this issue resolved? My Tacoma downshifts on hills when I want to coast and the engine revs higher than I would like.

 

Toyota assumes you want to save your brakes and use less fuel.

Stick shift for the win.

 

"characteristic" of the vehicle

 

Hi Guys - Sorry for delayed update. Toyota told me they would need several hours to try to recreate the shifting issue in order to apply the TSB, etc. I didn't find it worth the time, so I didn't have them review it further.

As an update, it's downshifting has gotten worse since the 5k service and I'm starting to find it very annoying. The ECU/TCU drops down to what is (IMHO) incorrect gear for proper engine braking, gas mileage, etc. I have a background in racing (cars, motorcycles, mountain bikes, etc). This may be both a positive and negative. I know what gear (typically) provides good performance, etc. I may have unrealistic expectations of how an OE vehicle should perform when it's making decisions.

I've also noticed downshifting on uphills is delayed well into the point of bogging down.

I believe any active system performing driving decisions (ABS, traction control, shifting, etc) should provide override and/or parameter programming options. Of course the industry thinks otherwise and they win.

This is my wife's truck which she is very happy with as is. Perhaps the easy answer is I avoid driving it .

 

Thanks for the update. Review the TSB and go to a different dealer and report the issues( i.e. slow shift from R to D when cold, erratic shifting in cruise control going uphill). My dealer applied the TSB without going and testing it. Unfortunately some dealers play by the rulebook and have to duplicate the issue to apply the TSB. Note: the TSB will not get rid of the engine braking much. I think it still brakes a little too much or stays in the lower gear a little longer than it should. But it doesn't annoy me enough to be pissed about it.... LOL

 

I hate when it downshifts going downhill, however I assumed it was because I have cruise control on! I want all the mpgs I can get, don't need the truck engine braking for me!

 

I agree. I drive down a steep hill by my house at least once a day and the truck downshifts to a lower gear than I would normally use. The only way I can avoid the downshift is to ride the brakes all the way down the hill, which will shorten my brake life dramatically.

I think Toyota should come up with a program change to eliminate unwanted engine braking.

 

Engine braking. Normal.

 

Yep, which really is backwards. If I'm on the brakes then fine, engine brake to help. If I'm not touching the brakes that means....wait for it....I DON'T WANT TO SLOW DOWN!

 

The only time my truck downshifts on a downhill is if I have cruise control set.

Without CC set the truck will go faster and faster until I use the brakes.

 

I have noticed this downshift while the cruise control is active and going down steep grades as well in my 2017 Tacoma Limited. I assumed that this is to maintain roughly, the set speed. This seems to work well on primary roads in my area, but I still have to go to manual shift mode when negotiating mountain top communities here. My 2004 4Runner would perform an automatic downshift only after I tapped the brakes. Personally, I like the feature since it helps me save my brakes and avoid speeding tickets. The RPM's do get have higher than I would have guessed, but nowhere near the redline growing up in the mountains I have always used engine braking to cut down on wear on my brakes as well as aide in traction control. And I'm not aware of any deleterious effects on the engine or transmission.

 

In my 2nd Gen you had to tap the brakes for it to downshift on decents. Tap the accelerator and it would upshift, typically with a clunk. Pretty annoying behaviour, I'm back in a manual truck now. Engine braking should be selectable with a tow/haul switch.