I’ve been slaving on a proto type. Room is tight in there, but I have something that seems to work. Lots of trial and error. Yes a welder was required, cut off wheels, carbide bit in a die grinder, used a lathe but you don’t “need” to (to make a nice centered hole in the end of the threaded press screw)
Started out as one of these.
Pictures of the final thing in action coming.
I used a tail housing from a late zx trans with the reverse lock out thingy, so getting the pin out initially to have an assembly to play with was easy. As long as you support the shift finger casting on the shaft very solidly against the inside of the housing, you can smack the end of the pin with the female end of a 1/4 drive 6” socket extension (so it stays on the end of the pin) with a 3 lb hammer and it pops right out. Any amount of bounce in that shaft and you’re banging on a loosing proposition. I used 1 minute of propane heat on it first.