Does anyone know much about these medium duty truck transmissions? There was a direct drive and an overdrive version, but don't know how to tell difference from outside. Thinking about using one in my divorced 205 crew cab...

Goto the dodgepowerwagon.com page. Somewhere on that page (or the ask on the furum) there is post to that question. I have never seen a NP540-OD but have seen several NP540-DD. The shift pattern is different and I believe they are stamped DD or OD. Also look into the Clark 280OVO.