Surface Actuated Downhole Adjustable Mud Motor

A downhole tool having a mechanically adjustable bend angle from the surface and method for actuation of the tool. The tool includes a knuckled joint between upper and lower housing assemblies and tapered setting ring upon which the lower housing assembly bears. As the setting ring is rotated with respect to the upper housing assembly, the lower assembly is tilted. A spline sub for connection to a drill string is included, which, upon a certain weigh on bit, axially moves within the tool housing to engage the tapered setting ring and force shoes radially outward to engage the formation and hold the tool stationary. The drill string is then rotated to rotate the setting ring, and thereby alter the tool bend angle. Toggles hold the setting ring fixed to the upper housing to maintain a given bend angle during drilling operations.