05 Trans Problem

[sheriffandy013]

Hey guys I posted inthe tranny section but im not getting much of a response. I have an early 05 with an A/T. Recently my mileage has gone way down and I though that my tranny was not going into overdrive. Someone said yesterday that is sounds like my tourque converter is locking up? I used to cruise at 75 mph at around 2k RPM but lately Im at like 2500 to 2700 when doing those speeds. I have an SCT that I have on a Mileage setting and I have even returned the truck to stock, still it does the same thing. Other than the above mentioned tranny seems to shift fine up and down thru the gears and my sct is not showing any codes and my tow/haul button is not flashing. Any ideas

TIA
ANdy