Abstract: A fluid shear coupling apparatus is disclosed herein which includes a driving member received within a working chamber defined by a driven member. The driven member is mounted with needle bearings to a shaft portion of the driving member to have the members rotatable about a common axis. The driving and driven members include complementary shaped and positioned fluid shear and thrust surfaces defining fluid shear and thrust chambers, respectively, therebetween and cooperable with shear fluid within the chamber to transmit torque and axial thrust loads between the members. The fluid shear surfaces are defined by interdigitated ridges and grooves. A shear fluid reservoir is located in the central portion of the driven member and passageways lead from an annular groove and cylindrical cavity adjacent the driving member back to the reservoir.