Patent ID: 7585243

Claim:
An automatic transmission mounted in a vehicle at the rear of an engine, in relation to the direction of forward travel of the vehicle, includes a speed change mechanism for shifting between a plurality of speeds by engaging and disengaging a plurality of clutches and brakes, wherein the speed change mechanism comprises: a cylindrical support; a first hydraulic servo formed by a first drum and a first piston which together define a first cylinder chamber, for operating one of the plurality of clutches; a main bearing mounted between an inner surface of a boss portion of the first drum and an outer surface of the cylindrical support, for rotatably supporting the first drum; and an auxiliary bearing press-fit into one end of the inner surface of the boss portion of the first drum and surrounding the cylindrical support with an annular gap therebetween in normal operation, the auxiliary bearing contacting the cylindrical support only when the first drum tilts and having a significantly shorter axial length than the axial length of the main bearing.