It is not a terribly difficult trans to build but replacing bushings without the correct tools can be tough and they will usually all need to be replaced. Be mindful of sprag wear and types of sprag for the power level you are building to. Check planetary pinions for excessive end play or wobble, the attrition rate is about 50 percent. Replace the pump gears, they come in four thicknesses so you will need to mike them out. Be mindful of clutch pack clearances, gear train end play and overall transmission end play. Replace all caged needle bearings. Above all, clean, clean clean!