I suggest you break the problem down into component pieces. First have a model with no thrust cone bearing that just has the helical teeth. The joints connected to the hole in the center of the gear will support and measure the axial force the helix generates. Or maybe you calculate that thrust force from equations. Second, have a model where the axial force is applied to the contact area of the thrust cones, and a tangential force to represent the friction. There is no contact in the model for the thrust cone. Each joint only holds a small cylindrical face at the center of each gear.