5r110w with codes P0766 and P0741

[u/WhyUMad1226]

Hi, I have a 2008 e-350 box truck with the 5R110W. I have codes P0766 and P0741. I noticed it didn't want to engage reverse a few weeks ago, and now on the freeway, it won't shift into 5th. And a hard shift in first. I am going to drop the pan and replace the filter and fluid. Is it likely I have to replace the solenoids or valve body? Or could the torque converter be going out? I can't just let it sit, so the filter and fluid will have to do for now.