10 speed trans not shifting

Only had my 24 Tundra limited about a week. Love the truck. I have noticed on the highway with cruise on 75 or so it seems like tranny stays in 8th instead of shifting up to 9th and 10th. Relatively flat roads. If I slide into shift mode and manually move to 10th there is stop in rpm and gas mileage goes up a little.
Any thoughts or suggestions? At 70 mph on flat land roads I can’t seem to get more than 19 mpg. That normal?

 

Should read “drop” in rpm and not “stop”.

 

Knowing RPM would be helpful to understand where in the load range you are operating.

 

While driving in 70-75 range rpm running close to 2000. When I manually put in 10th it runs about 1850

 

Lots of variables.

1. What drive mode are you in?
2. Do you have a head wind?
3. Is the road actually flat or is there a slight slope? It's easy to think it's flat when it's not.
4. How many miles are on the truck?
5. Is the truck completely stock or has it been modified? Are the tires the factory tires?
6. Are you using cruise control or manually operating the accelerator?
7. Have you verified the MPGs manually or are you going off the computer?

You do realize that when you move the shifter into S it automatically drops some gears, right? If you are shifting to S and then thinking the number it shows is the gear you were in, that is not how it works. You also can't force it to upshift into a higher gear. S mode works as a gear limiter, it doesn't actually shift the gear just because you move the selector up.

 

while it could indicate a problem if you will follow this anecdotal reasoning on my part. I have often noticed with several vehicles I've had and driving without cruise there is a break-over point in gear/rpm change where if i apply a little more power to force a gear change then settle back on the throttle the truck will stay in the higher gear. In essence the truck is riding right at the edge of a gear change but "just" not enough to force it to the next gear. "for what this is worth"
Also GODZILLA brings up several good points.

 

On the highway it only shifts into 10 th when your doing like 80. When you sport shift it puts it in 8th but just because you select 10, it doesn’t shift up till it’s ready. Watch your rpms. If your doing over 80 and your below 2000 rpms your probably in 10th

 

It seems a lot of guys don't understand this.

 

Been misunderstood for over a decade. People don't read their manuals or do any research before the buy stuff.

Not saying the OP didn't tgat. Just that it's not uncommon.

 

It seems people would figure it out after using it a while.

 

1. Mode:Normal
2. Side wind 8-10 mph
3. Not flat. Gently rolling north Okla.
4. Truck has 12,250 miles
5. No mods- factory tires
6. Using Cruise
7. As of yet doing all comparisons using computer readout of gas mileage goes.
Nd yes I am very aware that it downshifted gear or two when moving shifter to S.
With cruise control set at 75 the rpm’s are close to 2,000. I move shifter to S and of course rpm’s jump up due to downshift. So I move selector up a gear and let it settle in and then up another until the rpm’s match where it was when I started. Dash shift indicator is 8. As I read the posts I guess this may not actually be 8th gear. How can you accurately determine what gear you are actually in?
This is my first Toyota. Drove Honda Ridgelines from 2013 to 2025. And. Hyundai Santa Cruz past three months. Claustrophobia caused me to go find the Tundra. So far I really like it. I just want to understand its operating charteristics as much as possible.

 

its been that way forever with this.

 

Seems that to go to 80 mph will use much more power than 60 or even 70 to push the brick through the air. So to do this you need to put your foot into it and turn the boost up. Mileage wont be spectacular when boosting. Also, the transmission programming will probably force the downshift if you are looking for more power to get up to that speed. You will be fighting with the power demands and the transmission programming.

I like to slide in behind a transport trailer and get sucked along by the vacuum. Not a great view back there but really good mileage! (But seriously, don't do this)

 

The winds and rolling hills are going to penalize you. The EPA numbers are all estimates based on calculations for best case scenarios.

The only thing I'd suggest here is to hand calculate your mileage. The computers tend to be off by a bit, and it's never the same bit from one truck to the next.

One more question: For the MPGs, which setting are you using for the dash? It can show the trip MPG, tank MPG, or the lifetime MPG. ANY idle time will drastically tank that reading as well. For example, I operate my truck on the per tank display and my last tank of fuel had an overall average of 20 MPGs. The last couple days we've had a cold front and I've been idling the truck to warm it a little and get the seat heater going, but I'm not letting it idle like crazy. It's tanked my MPG down to 18, and the only change has been the 3-4 times I've idled it this week for around 5 minutes.

Not really a dead on way to determine your gear. S Mode just limits the top, so if you have it set to say 7th gear it won't go over that, but it will freely use any and all gears below the limit. So, if you are set to 10th it could still just stay in 8th if if determined that was the best gear for the conditions.


Overall, Toyota tends to program for MPGs even on their inefficient engines, so the truck is likely running in that lower gear to preserve mileage and performance as best it can.


If you want a little better mileage, but it will likely be more expensive, aim for ethanol free fuel. Corn isn't as efficient as dinosaurs.

 

You can use the Car Scanner app to tell you what gear it's in. Just need to have an OBD dongle plugged in.

 

Thanks to everyone for the explanations and tips. Helps me a bunch.
Have a great week and keep the shiny side up.

 

You too!

Try not to sweat the fuel economy. Here in Toyota Truck Land we value Smiles per gallon over the miles per gallon, even in the 3rd gen.

 

Ive got the MPG shit figured out.

boost like a mofo, when its empty, put in more

boost on

 

This is a fun way to do it, but if I was constantly in boost I'd have so many tickets. I'm empty 90% of time as of late, and the truck does pretty good at getting out of its own way.

 

I vacillate between optimizing mpg, and enjoying the power. I’m just so used to trying to get the best mpg I can, it’s hard to break the habit. I don’t hesitate to get into the boost pretty regularly.

 

I was 100% with you til I saw the cliche “smiles per gallon”.

 

just need to burb it and it just pulls O so nice right up to the speed limit, hardly have to crack 3,500 rpm, HA

may as well have some fun it, its only gasoline.

 

whatever the question is, boost is the answer

 

Yeah, I do give it more gas once it's up to temp, but my commute is so short that I baby it for that drive.

 

Problem is the automotive press can’t even get it right so it just incorrectly gets stated over and over again that it’s “sport mode” with manual shifters. Even TheTopher gets it wrong and I’m pretty sure SavageGeese does too; and SG tends to be super thorough about things.