Motor for horizontal directional drilling systems

A trenchless drilling system comprising:

• a mud lubricated motor comprising:
• a hollow body with a proximal open end, a distal open end, and a longitudinal axis therethrough and having an outer diameter and an inner diameter that is eccentric with respect to the outer diameter along the longitudinal axis;
• said hollow body comprising a sonde housing compartment recessed into a top surface thereof between the proximal open end and the distal open end;
• a lower mandrel comprising a distal end disposed within the hollow body and a proximal end;
• a drill bit attached to the proximal end of the lower mandrel;
• a shaft with a proximal end attached to the distal end of the lower mandrel and a distal end disposed along the longitudinal axis within the hollow body;
• an upper mandrel comprising a proximal end disposed within the hollow body and attached to the distal end of the shaft;
• a sonde housing cap removably secured to the sonde housing compartment via a spring-loaded mechanism or via a cap lock plate or via a combination thereof;
• and
• a sonde transmitter that is operably connected to a battery and is secured within the sonde housing compartment.