Hello
having some kind of issue with my trans and am hoping to find a solution. After driving around my o/d light came on and started flashing. it was shifting kind of weird. I turned it off and let it cool off. When I came back and turned it back on it was off. After driving around for a few minutes the light came back on. After driving it around and diagnosing I noticed it was only a issue between 1st gear. When I go from a complete stop and start going it won't shift out of first until I let off the gas compley. After that it shifts fine and the light dosent come on. If I let first rev too high then the light comes on. I've never experienced something like this and want some insight.

Thank you
(2005 ranger edge, 4.0 v6 with 5speed auto)