the number of shafts provided in heavy duty vehicles gear box is normally
Transmission (mechanics) Many transmissions and gears used in automotive and truck applications are contained in a cast iron case, though more frequently aluminium is used for lower weight especially in cars. There are usually three shafts: a mainshaft, a countershaft, and an idler shaft.
Gross vehicle weight rating The gross vehicle weight rating (GVWR), or gross vehicle mass (GVM) is the maximum operating weight/mass of a vehicle as specified by the manufacturer[1] including the vehicle's chassis, body, engine, engine fluids, fuel, accessories, driver, passengers and cargo but excluding that of any trailers.[2] The term is used for motor vehicles and trains.