Air breather for power transmission unit

摘要

A power transmission unit comprises a trans-axle casing rigidly secured to a cylinder block of an engine and having an upper compartment to contain a clutch for connection to a crankshaft of the engine and a lower compartment to contain a final drive gearing and a differential gear unit connected to each other, a transmission casing sealingly jointed at the upright front face thereof to the upright rear face of the trans-axle casing to contain a change-speed gear transmission drivingly connected to an output shaft of the clutch and coaxially connected to the final drive gearing, and an intermediate plate interposed between the casings to partly support thereon the output shaft of the clutch and the component shafts of the change-speed gear transmission. In the transmission unit, an air breather is provided on a head portion of the intermediate plate to prevent the flow of lubrication oil out from the casings and entrance of water into the casings.