All of the new ratio drive and driven gears are then carefully pressed onto their respective shafts with a shop press, so as not to damage any bearings or accessories. When both of the shafts are complete, simply reverse the disassembly process. Some special gaskets, sealant and tools are required, so it's highly recommended that you go to an experienced shop. There are special ways to remove each and every part in the assembly. A single mistake can be costly.