2009 Kodiak Allison 1000 P0741 Fault: Check Engine Light Activates on Hills, Idle Drops, Repeats After Restart

I brought my 2009 Kodiak with Allison 1000 transmission in for service and was told the issue is code P0741, indicating a pressure sensor malfunction related to the torque converter. I replaced the transmission with a new certified unit, but within a few days, the same symptoms returned. When the vehicle has weight on it—especially when climbing hills—the check engine light activates with an arrow pointing downward through the engine icon. The engine idles down and loses power significantly. After restarting, the issue disappears temporarily but returns whenever I attempt to accelerate. I've taken it back to the same dealership, only to be met with delays and vague responses—no clear diagnosis or action plan. Given this recurring behavior, I'm now considering replacing the speed sensors as a potential fix. Any insights from owners of 2009 Kodiak models with Allison 1000 transmissions would be greatly appreciated.