Replacement Truth window operator crank mechanism

I have 2 casement windows with cranks that won't close all the way - 1 is right handed and 1 is left handed. I think the gears are stripped. The long arm measures approximately 13 inches. Do you have replacement parts - I think I need complete package - crank, cover and screws as well as arms. It looks like I woold have to remove bottom piece of wood from trim work to gain access. Thanks