Not all of the rods on 3600's have the tab, for those that do not there is a wire "S" piece that hooks through a hole in the frame support and the other end hooks into the clevis on the rod. Sorry I don't have a better pic and I am out of the country at this time so truck pic is not possible.
https://www.flickr.com/photos/advance-design_parts_co/14214865124/in/album-72157631867396207/