I just noticed this issue this morning. I noticed my truck was running at much higher RPM than normal at highway speed (65-70 MPH). I made a couple of stops and after turning the truck back on, the transmission light came on. I decided to limp on home after picking up some feed because we are leaving town for the week.

On the way home, I'm assuming it wouldn't shift into higher gears (past 3rd). I had to go about 55 at about 3600 RPM.

Truck has about 92K on it. I never heard any clicking or grinding in the gears and never noticed any gear slippage. I tried to game the system and put the transmission into 7th automatically when I left after dropping off the feed but after trying to get up to speed, it would automatically o back to Drive and the issue would persist.

Any of y'all have any ideas on what I'm looking at here?

Could be a shift solenoid issue. I would get the code information and go from there.

Check to make sure you didn't accidentally hit the tow mode located on the shifter.

I made sure to check that. I pushed it to make sure it wasn't on.

The dealership (ugh, i know) may be able to perform a software update to fix that. See if you can get any codes to help