Alan, thank you for the reply.
If you are referring to the little gold colored 10x12x0.25mm shim (page 17 of the manual) placed between the top of the lower bearing block and the bottom of the main tail belt pulley then yes, that shim is in place along with the two auto hub delrin shims.
I went back and pulled up and pushed down on the main gear and there is definitely up and down play there which could also explain the issue. Maybe I need to find another small shim that would fit between the bottom of the middle main shaft bearing block and the top of the main gear?
Thanks,
Shawn