I have an extra trans I just bought from a yard, thing is I don't know what a main drive gear looks loike or a syncro. Are there any folks out there that still know how to rebuild these trans. I would hate toconvert to 4 speed as this is my grand fathers truck and I only remember the 3 speed in there, my kidsonly know the 3 speed I have to fix it before they get it or I will wind up with a 350/350 comminaton.