Abstract: In a planetary differential gear system using helical gears, a clutch is interposed between a carrier for planetary gears and a differential casing, and adapted to be engaged by an axial thrust force produced by a sun gear. First and second axle shafts are provided with splined internal ends which are received in complementary bores of the sun gear and the carrier, respectively. The first axle shaft is received in a bore of the differential casing so as to be freely slidable and rotatable jointly with the sun gear. Therefore, the thrust force produced by the sun gear when a drive input is applied to the differential system can be transmitted to the friction clutch without being obstructed by the friction produced by the splined coupling between the first axle shaft and the sun gear, or disturbed by any unpredictable force of engagement between the first axle shaft and the sun gear.

Abstract: A system for lubricating a transmission for a vehicle includes an auxiliary oil reservoir placed in the transmission case apart from transmission gears, an oil pump in the transmission case operated interlockingly with an output shaft of the transmission for pumping lubricating oil stored in the bottom of the case into the auxiliary oil reservoir, and a circulating means provided in the auxiliary oil reservoir for regulating the amount of oil circulated from the auxiliary oil reservoir into the transmission case, such that the amount of oil in the auxiliary oil reservoir is increased or decreased in accordance with a respective increase or decrease in the amount of oil discharged from the oil pump.

Abstract: A multiple-disk clutch apparatus including an input-side rotatable member having a clutch disk pressing surface, a pressure plate attached to the input-side rotatable member and disposed on an axially rear side opposing the pressing surface, a plurality of clutch disks disposed between the pressing surface and the pressure plate with an intermediate plate being interposed between the clutch disks, and a stopper member for restricting an axially rearward return position of the intermediate plate at the time of clutch disengagement. The stopper member is mounted on the input side rotatable member via a one-way mechanism which allows an axially forward movement of the stopper member but which restricts an axially rearward movement thereof. A holder for holding the one-way mechanism can be mounted on the input side rotatable member so as to be movable axially rearward against a spring. A restriction portion for restricting an axially forward movement of the holder can be formed in the input side rotatable member.