You need an 1 7/8" socket, fairly deep. The threads are reverse, and you need an impact wrench. Take the primary cover off and put a metal strap between the clutch basket and compensater sprocket so that it binds and keep the tranny sprocket from turning. Ain't no piece of cake.
On an '07 96" we did recently (which are now RH thread) deep socket, tool to hold mainshaft, 1/2 breaker bar... none worked... had to apply over 300 degrees of heat to break the locktite. Luckily... no damage to the mainshaft seal.