The rear bolt actually threads into a nut that is welded to the cab floor, there is no separate nut. It should be the smaller of the 2. The protruding part of the rear rectangular pad goes down, then the spacer acts as an alignment fot the 2 rubber peices. I will admit, the manual can be difficult to read, especially if you are not familliar with vehicle assembly. Sheet 47.00, section A-A at the lower left side of the page gives the best picture of how the rear mount goes together.
