Downshifting when braking?

T

teygabroad

New member
In some situations my truck downshifts when I apply the brakes. There happens to be a downhill by my house and the speed limit changes. So when I crest over the top of the hill I apply the brakes some to slow down. I am slowing down from ~50mph to 40mph. I am in 4 hi and this is on a paved road. I can get the truck to do this pretty consistently. Basically my complaint is that the truck shouldn’t downshift, it seems unnecessary. Has anyone encountered this same scenario? I am just curious if all of the 5th gen 4runners do this. When I apply the brakes I am doing it gently, I am not slamming on the brakes. This is not a super steep hill. The transmission is in D. Maybe this is already covered somewhere else on the forum but I couldn’t find it anywhere. Thanks in advance for any info you can provide.
 
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I am most likely and idiot but when I search the owners manual and look in the index I don't see anything regarding grade logic. Can you be more specific where in the owners manual? Thank you very much.
 
Not even sure the manual goes into detail.

I have a 4th, but we have this as well. All it is are nanny devices. The 4runner has pitch and yaw sensors and when it thinks your going to fast down a hill, and you touch the brakes, it tries to "help" you by doing a downshift to give you engine braking.

You get used to it.....
 
Most modern vehicles I've been in do this. It helps for the people who come down the ski mountain and refuse to downshift and half way down you can smell their brakes burning.
 
What it does is lock up the torque convertor so the engine braking works better. It does not actually shift to a lower gear. I live in a mountainous area and this feature is awsome. When going down a big grade trying to maintain a certain speed i just tap the brakes to apply this feature and it really maintains the speed better than riding the brakes. It works best if you shift it out of overdrive going down grades. My 2011 Avalon does not have this feature and I miss it a lot. To people living in flat country this feature will not be as usefull.
 
Actually, it will shift. 3rd is the lowest I've encountered. Sometimes it doesn't like to upshift after this until you're really spinning your tach.
I consider it a reminder to use the Sequential Shift (S) mode when in hilly terrain.

Why are you doing 50 in 4H on a paved road?
 
It's actually a great feature, especially if you tow or haul heavy loads.

Give your brakes a break on those long hills!
 
I am in 2 hi not 4 hi ...... like I said I am a moron. My truck definetely downshifts when it does this. I can feel it and hear it. I guess I will get used to it. My last truck was a 2001 pathfinder, it did not have this feature. It is a nice feature but in this particular scenario it is a little annoying and it just so happens to be on a road I drive on every day. Otherwise it seems like a good feature. Thanks for your replies.
 
What you are experiencing is indeed downshifting. It is an odd sensation, and I've never owned a vehicle where this was so noticeable.

Mine occurs just below 40 mph and has nothing to do with braking. Just let the truck coast down from, say 42 mph, and right at ~39 mph you'll feel it shift into 4th. Watch the tach, at the same time as the downshift, the tach bumps up a few hundred rpm. Now accelerate gently, you'll feel it upshift back to 5th and the tach will drop accordingly. Continuing to coast down will also shift down to 3rd, watch the tach.

If you're driving around town right at 40 mph, this constant up/downshifting gets .... well ... odd, to me. In town, I drive in 4th now.
 
03_4x4Runner said:
What it does is lock up the torque convertor so the engine braking works better. It does not actually shift to a lower gear. I live in a mountainous area and this feature is awsome. When going down a big grade trying to maintain a certain speed i just tap the brakes to apply this feature and it really maintains the speed better than riding the brakes. It works best if you shift it out of overdrive going down grades. My 2011 Avalon does not have this feature and I miss it a lot. To people living in flat country this feature will not be as usefull.
Click to expand...

Just fyi that it does in fact downshift. You can confirm this by moving your shifter into that gear and there's no change. Thus, confirmed that it is a downshift. Try it out.

Agreed with the rest of your post however.
 
stanleybb50 said:
Just fyi that it does in fact downshift. You can confirm this by moving your shifter into that gear and there's no change. Thus, confirmed that it is a downshift. Try it out.

Agreed with the rest of your post however.
Click to expand...

I did not realize at the time I posted that I was in the 5th gen section. I was refering to what my 4th gen V8 does. The 5th gen may indeed downshift.
 
if the transmission was locking and unlocking the TCC that often it would over heat and burn up the transmission very quickly. i can assure you it does not do that.
 
rebelbowtie said:
if the transmission was locking and unlocking the TCC that often it would over heat and burn up the transmission very quickly. i can assure you it does not do that.
Click to expand...

This is not true, the lock up convertor locks and unlocks many times on any trip. Every time the gas is hit beyond a certain point it unlocks and it unlocks on upshifts. I do not think it is used in 1st and 2nd gear. Any time you climb a hill it unlocks if it is lugging at all, it is not usually noticable but if you watch the tach you can see when this happens. If that is not enough to maintain speed then it downshifts to a lower gear.
 
03_4x4Runner said:
This is not true, the lock up convertor locks and unlocks many times on any trip. Every time the gas is hit beyond a certain point it unlocks and it unlocks on upshifts. I do not think it is used in 1st and 2nd gear. Any time you climb a hill it unlocks if it is lugging at all, it is not usually noticable but if you watch the tach you can see when this happens. If that is not enough to maintain speed then it downshifts to a lower gear.
Click to expand...

unlocking and locking the converter builds heat. sure it happens many time while driving, but if it was doing this to slow down the vehicle or act as an engine brake it would build lots of heat.
 
rebelbowtie said:
unlocking and locking the converter builds heat. sure it happens many time while driving, but if it was doing this to slow down the vehicle or act as an engine brake it would build lots of heat.
Click to expand...

When the convertor is locked up no heat is generated. It is locked up like a engaged clutch in a manual trans. Heat is built up when the convertor is slipping under acceleration with the clutch unlocked. The clutch is engaged by a solenoid controlled by the computer.
 
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