Originally Posted by YARO

Have you ever taken apart a tranny before?
remove casing, undo shift selector, remove reverse & idler, pull the mainsheft/countershaft/and forks up. Once you have the main and counter shaft out remove the top sections of each one. 5th is the very last gear in both shaft under some bearings, sychros, collar. Need to change both sides out. You will need a 32mm impact socket or with some luck in a bench bolted vise a braker bar for the countershaft. You might need a puller for the gears sometime they are stubbern to come off.