Upshift Downshift RPM Pausing….2022 SR5

Hello folks. Am I paranoid about this unnecessarily?

2022 Tundra SR5, had it new just less than a year. Only using it mainly for towing a 5000 lb RV after break in. I notice that when it downshifts on the highway at about 60 mph, the rpm goes from 1600 to about 2250, then to 2000. It’s only a short pause at this higher 2250 rpm, maybe a half second, to maximum one second.

But differently on the subsequent up shift, the rpm goes from about 2200 to about 1800, then to 1600. Again only a short pause of maybe half a second. However the “paused” rpm is between the two rpm’s in this case.

In Tow mode. Seems to also occur non tow mode, and without trailering.

The only vehicle I can compare it to is a 2012 civic, here the transmission changes very smoothly, with no pausing between the rpm's

is this normal? Should I be concerned?

Stan

 

Sounds like it may not be actual shifts, but rather locking of the torque converter, which accounts for about a 250 rpm decrease when the TC locks up. Its hard to know without monitoring engine data and looking at the shift status and the TC lockup status.

 

100% it’s torque converter locking up.

 

Thanks Ric & XC

so this period of transmission slippage, less than 1 second, between these gears, you think that is normal? I should not be concerned?

Stan

 

By not ignoring your Sequential Shifter and using it for it's intended purpose, will certainly help eliminate all those needless shifts up and down on an unlocked torque converter. Make the effort, it'll be well worth it.

 

It’s not the transmission slipping but the connection between the engine and transmission. What you see if the engine speed dropping down to match the input shaft speed of the transmission.

 

CMikeB. I tried S8 today Gainesville to Sebring in Florida, tow haul mode with a 5000 lb trailer. I really did not see any difference from all the driving I’ve done in D mode. Still 1600 rpm at 60 mph level road, downshifts to 2000 rpm for the hills. I’m finding S mode did not seem to reduce “needless shifts up and down”.
Am I misunderstanding you?

 

S mode on the shifter only locks out the top gear. So S8 doesn’t let it go past 8 to 9 or 10. Tow mode doesn’t go past 8 either so that’s why you felt it didn’t do anything.

 

On my 2010 SR5, "S" Mode allows gear selections for all 6. It doesn't just "lock out the top gear." Since few "drivers" make the effort, the new models are probably different and limit it's usefulness.

 

CMike B

Ok I see your 2915 may be different. My 2023 is a 10 speed. I tow a trailer. Using S7 allows 1 to 7th gear, at 60 mph that’s 2000 rpm, sure I could use S7 and prevent 8th gear, and I doubt the transmission would ever shift down to 6 except steeper hills.

But 8th gear is 1600 rpm, tow mode with a trailer selects 8 gear in D for level ish highways. If I held it to 7th that costs extra fuel I think. And I doubt see excessive down shift to 7 in D mode.

so I’m not sure it’s worth it for me.

 

Your S-mode works the same way. It only locks the maximum the trans will go up to.

 

My S mode allows me to choose any of the 6 gears that are correct for speed, load and road conditions.. Up or down.

 

We are the saying the same thing. You can choose the gear 1-6 and we can choose the gear 1-10. Whatever gear (S1-S6 or S1-S10) you select is locked out as the top gear. The vehicle still shifts into the other gears and stops at the gear you selected. It’s not a true manual mode that lets you select a gear and it holds that gear.

 

Yes, and all that does is limit the maximum gear. Put it in S4, and slow down to a stop. It will shift down through the gear like normal. Then when you start driving it will shift up through the gears, like normal, until it hits 4th. It won't shift beyond that unless you change the setting. This is how S-mode works. It does not manually shift the gears unless you are keeping the max gear selected low and then bumping it up when the truck would shift anyway.