Shift Kit for a 727

Just a thought, but check the adjustment on your 2nd gear band. The factory adjustment specs are quite loose to give you a smooth shift. Add a shift kit (or valve body) and you can tighten up that adjustment. I spent 15 plus years with Chrysler rebuilding tranys in a dealership. There are many things that come into play when wanting a positive 2nd gear shift. Springs in the acumulator which activates the band, etc, not knowing what mods are in your trany the band adjusment seems to be the easiest thing to check.
Good luck!