There are two places for a frame partial VIN number on the frame. One place is on top of the frame under the cab. This one is hard to see with the cab on.
The same number will also be on top of the frame in the engine compartment. It is much easier to find and see. Driver side top of frame across from the front of the engine block. Here is a pic of mine. My PS pump is what you see at the top of the pic.
