IHC (Mehano) Thunder Bolt Set

SD-40 use # 22 Coupler, cars use # 28 Coupler.
For engine remove the truck sideframe by using a thin bladed screwdriver and pry the rear of the sideframe over the tab. The wheels should stay in the truck, remove and discard coupler. The #22 Coupler will be mounted on the top of the sideframe. Measure along the centerline back .175" from the front edge of the sideframe's coupler box. Use a #50 drill and drill a hole through the top of the coupler box, it will go through the post on the underside. Tap the hole with a 2-56 tap. Assemble the #22 Coupler to the top of the coupler box with the coupler first and then the spring and the lid. Secure with  the plastic 2-56 screw and trim to the height of the post. Check for proper function. Make sure the wheels are in their proper location and replace the sideframe on the truck and snap it in place. Check for correct coupler height, function, and clearance and make any adjustments necessary.

For cars use #28 Coupler install with centering spring on top.