what causes the transmission to shift properly ?

What is your question?

ive changed out the slave cylinder and the hydraulic clutch line, and the clutch plate but im still having an issue with shifting. if i start the truck in first gear it wont shift into any other gears, if i start it in second it will go into the rest but its hard to get in the gear and it grinds while trying to go into revese... and the gear oil isnt low ???????