A keyless timing gear assembly for securing a bull gear to a crankshaft of a power end of a reciprocating pump assembly, the keyless timing gear assembly including at least one actuator, an expansion member and at least one wedge member disposed between the at least one actuator and the expansion member, the wedge member having a sloped surface to slideably engage a corresponding sloped surface on the expansion member such that, in response to actuation of the at least one actuator, the at least one wedge member exerts a force on the expansion member for securing a bull gear to a crankshaft.