still no definite answer

i have noticed something that bothers me, if im driving and i set the cruise control at say 65 and theres a hill coming up, the trucks rpms will raise and the truck will downshift to keep the truck at 65 while going up the hill, but once leveled back out the rpms will not drop all the way back down they will hold that higher rpm almost like its holding/ hung up on a gear.... i will then have to tap the brakes to disengage cruise control then reset the cruise again, has anyone experienced this? it was very noticeable when i was running 35s but i have since put my stocks back on and it still does it on a steep hill but not as often, it makes me think something is wrong with my transmission but if im not in cruise control everything shifts like its supposed to so im wondering if anyone has experienced this? is there a fix for this? if i do it in s6 it shifts like its supposed to only when in cruise control it does this, its like it doesnt want to go back into overdrive, i know im beating a dead horse but ive talked to a few tundra owners and they have no clue what im talking about. i know its gonna gear hunt but my problem is it shifting back into overdrive once leved back out...

 

Mine doesn't like to downshift when using cruise, it drops RPM so low that it'll stumble a bit before it drops a gear. I'm looking for a way to monitor TC lockup so I know what it's doing.

 

that's something different but can understand your concern I just want to know why mine is doing this it's absolutely aggravating.

 

My 2020 use to do that. There is nothing wrong with your transmission. It’s just a software issue. I noticed it more when towing. I would have to bump the cruise off then it would shift, then engage the cruise again and yes it’s annoying. Strange through I haven’t noticed it on my 2016.

 

Exactly why I don't use cruise. I like to know when my accelerator is going to be stomped on to make the truck downshift and how I can level out the throttle to make it shift back into a higher gear. Especially when towing.

Furthermore, I've found that living in the mountains driving on winding roads and always up and down mountain passes, cruise just isn't an aware enough software program to handle effective throttle response on a consistent basis. YMMV though.

 

Exactly, same driving conditions here. I don’t use cruise unless I’m in Florida or some other flat state. I would rather not peg 5000 rpm on every up hill, cruise is useless in the mountains.

 

My 17 doesn’t do that. Downshifts if needed for a hill, once leveled off, it upshifts and I’m back where I started. I have 35’s on mine too. My wife’s Lexus does something I hate: when going DOWN a hill, the cruise will downshift to slow the car. It annoying. Once leveled out, it gets really confused on shifting and I have to turn the cruise off/on again as well.

 

My 2017 will do that after plateauing out at the top of a hill. Might take, oh, say, 20 seconds and it then downshifts back into cruise gear (6th).

However as others have said I don't want the computer determining when to stomp on the throttle. And often it's a multi lane road (think: interstate highway) and there's other vehicles that might go total retard and cut over in front of me (I'm talking to you idiot 18 wheel truck driver). So I disengage the cruise control when I see the hill approaching. Re-engage after plateauing out. Easy-peasy.

 

Mine does this as well. I believe that it's just the AI functionality that's programmed into the TCU. It's probably not actually downshifting, the torque converter is just unlocking and with the programming, the conditions are not being met for it to decide to lock back up.

I've noticed that on mine, if I set the cruise before the TC locks, it tends to hang as described and won't lock until I encounter a slight downhill grade even when the road "appears" flat. If I wait until the TC locks, then set the cruise, it will stay locked.

I can use my cruise control just fine in the mountains to climb 5% grades and it shifts very much like what it would were I not using it. I am running stock sized tires though too....

 

My 21 does the same thing, it's just part of the geriatric programming that Toyota used

 

Same thing here on my 18.

 

If this started after going back to stock from 35's, you may be able to reset things by disconnecting the battery for 15 minutes and reconnecting. This will force the software to relearn things and may resolve the issue.

 

The OP said it was worse running 35s.

 

Toyota's cruise control makes me sick even in a flat state.

 

the problem is not the downshifting i could care less about that the problem is the fact that once leveled back out, it doesnt want to lock back up I don't understand why it does this i would like to get it fixed, makes me think my tranny is damaged or something, others have stated the ott tune fixed theirs but I've had mine ott tuned and it still does it it drives me crazy and im ocd when it comes to my truck. anyone else have a video of their truck Doing what mine does??

 

My 16 4Runner did that, it was also lifted up front. I’m guessing yours is too since you use to have 35’s. I feel once the road is “leveled out” your truck actually isn’t with the lift. Always felt there was some type of level sensor possibly playing against it.

 

Mine did it stock and with OTT.

 

have you had your transmission serviced?

 

Nah not yet. Only got 80k on it. Gonna wait until my new valvebody shows up and do it then.

 

No issues with mine, but I don't monitor with an OCD mentality I guess. So maybe it does it also. I run 33s.

I have noticed if I set it to 80, the speedo will stay at 79 regardless, and to get it to 80, I have to set cruise to 81.

 

why are you putting a new valvebody on it???

 

idk that's the weird part some ppl says they've noticed it some don't, so idk if its normal or what

 

do you haver a calibrator to correct speedo?

 

i wonder if this is a thing????

 

I wonder if it's a speedometer problem maybe the larger tires are throwing off the speedometer causing the cruise control not to read the speed right???????? anyone have any experience with this?

 

Upgrading to a performance version.

 

Mine does the same thing

 

Mine does that in cruise control. Eventually it goes into the right gear. I don’t use cruise control while towing. If something happens I need to have control immediately. I’ve read where if towing in cruise control and something happens like a flat tire, or a slippery spot, shit can go wrong in a heartbeat.

 

im not towing anything im just putting it in cruise on the interstate and its doing it

 

I do. Added one since I’m running 35’s.