Originally Posted by Mankster

These are the mission critical steps, measure twice....
Flip the middle deck over and lay it on a flat surface to make sure the top of the middle deck is entirely flat and not warped a little (mine was, and I had to take it into account when measuring the holes to be drilled out for the shafts etc..). Measure the distance between the two output shaft on the drive gearbox, mine did not match the dimensions in the drawings used to mark holes to be drilled in the middle deck.