Oil flow control device for power transmissions

Claim 1

In a power transmission unit for a motor vehicle comprising: a transmission casing shaped to conform with a change-speed gearing contained therein, said change-speed gearing including an output mainshaft rotatably supported from an upright end wall of said casing; and an extension housing secured in a fluid-tight manner at its upright front seating face to said upright end wall to contain one end of said mainshaft extending therein from said upright end wall, said extension housing forming a lubricant chamber in open communication with the interior of said casing through the upper portion of said upright end wall; the improvement wherein the bottom wall of said transmission casing is formed therein with a cavity opening toward said lubricant chamber and with a through hole across said cavity to open said lubricant chamber toward the interior of said casing and exterior therethrough; and a plug element is coupled with said through hole in a fluid-tight manner to close said through hole, whereby when said plug element is partly released outwardly, said lubricant chamber is communicated with the interior of said casing through said cavity and said through hole.