Paul, but if you just want to bump the engine while working under the hood, it's common and easy to use a large screw driver or other pry tool between the button lever on the starter and the floor to activate the starter Bill
Here is a
Cut-away view of starter motor drive & Mechanical starter linkage--- scroll down to view picture.
Like
red58 said, You have to use a pry tool between the starter lever arm and return spring and pry it over to activate starter.
Or possibly clamp a vise-grip pliers to the end of the starter lever arm and apply downward force to pliers to activate starter.
Safety Note: Make sure the truck is in neutral.
