Strange transmission behavior lately

I just noticed in the last few days driving around the city the truck seems to hold a lower gear all the time at less than highway speeds, it acts like the ECT is on. If I press the ECT button now it has no effect, it used to downshift a gear and get kinda jumpy off the line starting out. I'm tuned with KDMax 9(I think) for a few years and everything else works normally, it will get into 6th on the highway with no issues or delays. No work mechanical or electrical on the truck since fall when I replaced the head unit. I do an ATF drain and fill about every 20,000, currently have about 80,000 miles. Is this a problem or just an aging transmission?

 

Does the ECT light on the dash go on and off when you push the button?

Also, have you tried unhooking the Negative battery cable for a minute?

 

Yes the lights goes on and off with the button like normal, but I haven't tried to disconnect the battery. I'll try that after I get home from work. Thanks

 

Have you recently changed your driving habits, i.e. much more city driving than open road?
Maybe your Taco is learning the newer conditions.

 

Nope, same old boring route to and from work, then up to the cabin on the weekends like I've done since I bought the truck new.