a unitary tubular mandrel adapted to connect to a power output of downhole motor, said mandrel having:

an upper end proximal to the downhole motor power output,

a lower end with a male pin connector distal from the downhole motor,

a longitudinal passage through the mandrel from the upper end to the lower end,

at least one circumferential ring projecting radially outward from an outer surface of the tubular mandrel, said ring having an upper shoulder and a lower shoulder and a radial surface;

a circumferential upper thrust bushing contacting the upper shoulder of the ring;

a circumferential lower thrust bushing contacting the lower shoulder of the ring;

an upper thrust bearing contacting the upper thrust bushing;

a lower thrust bearing contacting the lower thrust bushing; and

a tubular bearing housing having a longitudinal passage from an upper end of the housing to a lower end of the housing, said passage having a lower portion with an internal diameter adapted to receive the lower end of the mandrel and said housing having an upper portion with a larger internal diameter adapted to receive the radial surface of the circumferential ring projecting from the mandrel, and said housing adapted to allow the male pin connector of the mandrel to be disposed outside of the lower end of the bearing housing.