On my Toploader applications, I move rail detent notches when I install faceplates to reflect the shorter slider travel. Much the same as with the Saginaw, a steeper notch wall in the rail makes it much harder to pull a Toploader out of gear. The Toploaders also have different shaped ends on the interlock and detent pins, the shape where they engage the rail notches also have an effect on how hard it is to pull the trans out of gear. I've never had an A855 in my hands, but I would not hesitate to massage the parts to keep it from popping out of high gear.
