A magnetorheological fluid damper is provided which permits effective control of damping while minimizing assembly size and costs by including a thin-walled insert in a flow gap formed between a flux ring and a piston body. The insert may include a thin-walled tubular insert having a generally smooth cylindrical shape for increasing the shear surface area. Alternatively, a corrugated insert may be provided having corrugations formed by edges extending axially along the insert. The corrugations may be formed in a variety of locations, sizes, shapes and spacings along the axial extent of the insert and the circumference of the insert. The corrugations advantageously effectively align the insert within the flow gap and also function to securely connect the flux ring to the piston body without the use of other devices such as plates thereby reducing the size and cost of the assembly.