Feels like Tow/Haul mode stays on

[14ChevSilv]

Recently I had to replace the torque converter on my 2014 Silverado. After getting the truck back, it seemed sluggish and running somewhat high RPM's before shifting. As I got to thinking more about it yesterday, it dawned on me that it seemed to feel like I was in Tow/Haul mode but Tow/Haul mode was not on. I turned on Tow/Haul and it seemed to drop the RPM's at first and drive normal before going back to running in Tow/Haul mode since it was switched on. I turned it back off at this point and was running around 1400 RPM's at speed limit. This morning, it felt the same way, I switched on Tow/Haul mode (RPM up as normal) and switched it right back off and the RPM'S dropped down to around 1400 RPM's and it ran fine on my 25 mile drive to work. Any ideas what I could be dealing with?