Abstract: A downhole mud motor is disclosed which has an improved bearing mandrel and a bearing stop to transfer a larger percentage of the weight of the drill string to the bit. Also improve sealing systems for the transmission section and bearing section prevent drilling mud from entering critical components. A piston stop is provided to prevent the piston from damaging any parts as the piston moves under pressure. A compensating pressure disk is placed in the lower housing to prevent pressure from building up in the bearing section. A grooved ball seat is provided in the transmission to allow for greater flow of lubricant around the ball bearings.

Abstract: A bottom hole assembly for horizontal directional drilling that improves the accuracy of surveying while boring by enabling the progress of the bore to be monitored and tracked with the aid of a sonde. In one embodiment the sonde is received in the wall of a area of a mud motor surrounding the bearing mandrel, in another embodiment the sonde is carried in the wall of a collar surrounding the bearing mandrel housing, and in an additional embodiment the sonde is carried in an adapter between the bearing mandrel and the bit.