GM-39442 is a hardened steel adapter which fits into the mainshaft or countershaft end to protect the shaft during disassembly. GM-39442 is designed to supply a press contact for service to the mainshaft or countershaft. GM-39442 is installed into the end of the mainshaft or the countershaft during disassembly. A hydraulic press is used to remove bearings or gears, by contacting the surface of GM-39442 to apply pressure for disassembly.