Why Does My Truck Shift Really Hard Only From First To Second?

Regardless of clutch actuation system you have, it is obviously not working properly for you. Manual trans first gear actually engages the most gears in a trans. So when you step on clutch, you are disengaging most amount of "metal touching metal" in trans. As you upshift into higher gears, less gears/movement is used. Also, a syncro could be going bad in the trans. At a slow speed, can you down shift from second to first without same problem? Trans are tough to diagnose from the outside unfortunately. You could drop the pan and inspect for any metal shavings, worn/shiny spots on gears to give you a direction to go in. Ain't no fun as they say.