A two speed transmission including a direct drive and a reduced speed ratio. The transmission is directly coupled to a variable speed engine crankshaft and includes pulleys thereon for the driving of auxiliary engine equipment. A first drive train includes planetary gearing and a one-way clutch while direct drive is provided by a wrap spring coupling cylindrical surfaces on the transmission input and transmission output axially adjacent and coterminous. The wrap spring includes an element having a flat side for engagement of the cylindrical surfaces. Two actuator mechanisms are illustrated employing centrifugal weights to result in advancement of one end of the wrap spring to tighten same into coupling engagements at low engine speeds. At higher engine speeds, the actuator mechanism releases the wrap spring from the cylindrical surfaces for drive through the planetary gearing.