Has anybody else seen this?
So on my way home from work, there is a dual lane, pretty long steady incline (fairly steep). The speed limit is 50, so I set my cruise to 50 going up. I noticed that the truck will not downshift but stay in 6th gear all the way up at around 1,200 rpm. It seemed a little low on the rpm's for how steep the hill is, so one day (about a week ago) I decided to use the "-" button of the select trans switch to make it go into 5th. RPM's go to ~ 2,000, and I immediately saw an increase in the green bar indicating the instant fuel mileage. I've repeated it every day since with the same result. So I get better mpg's manually shifting into 5th gear in that specific situation.
Kind of interesting. Not like a huge jump by any means, but definitely a noticeable one. Anybody else?

 

I've only had my truck for a few hours but I can see how a lot of people have a hard time getting used to the way this thing shifts. I hope to get used to it but it is definitely different than any other automatic I have ever owned, and that's all I've owned for a long time.

 

I notice similar events going through my neighborhood headed towards the freeway. Traveling at 30-35 the truck has already upsfifted to the highest gear it can stand and the MPG's are lower than they are when traveling at 70 on the freeway.

 

I've noticed the same. It seems to be calibrated to shift into the highest gear possible as quickly as possible. I've had to lockout 6th gear numerous times (and I've only had the truck for 3 weeks!) when I've been in traffic that doesn't maintain a constant speed. Even with the 3.73 rear, these trucks are a bit heavy for 6th gear at 35 mph.

 

I've noticed and done the same exact thing. In town, I lock out 5th and 6th. I have also manually down shifted on hills and seen the mpg increase, plus sound a lot "easier" on the tranny and motor. I am still super satisfied with the truck. 13,328 miles and counting. I will be taking her to Vancouver BC this weekend and San Diego the following weekend. Can't wait!

 

Just wondering if anyone has tried locking out 6th all the time and see what kind of fuel mileage difference there is.

In theory, a higher gear will provide more economy, but as engine load goes up the fuel mixture gets richer and can comsume more fuel at the same RPM. the obvservations above seem to support this thoeory. By increasing the RPM to reduce engine load, the fuel mixture can run closer to stoich and economy can increase.

I'd be curious what kind of economy increase 6th gear provides over all.

anyone wanna lock out 6th all together and drive it for a week or so and compare mileage?

i'd do it ... but 2010's don't have select shift

 

IMO, in the newer shift stratagies they tried to get a happy medium if you will. Some people were complaining about too much shifting. So I'm sure sometimes it doesn't shift when it would be more economical, but not greatly so, to cut down a bit on the shifts.

 

Yeah, I could see that. It makes sense.