I just put my cab back onto my 37 frame 2 weeks ago. I too had some difficulty getting the rear cab mounting holes to line up to the frame holes. They were off about 1/4" on the driver side & 1/8" on the passenger side. I finally figured out the door gap had retracted at the bottom. I took the sills off when I removed the cab several years ago, not thinking this may occur. To solve this problem, I removed the 3 screws on the bottom of the floor on each side where the blocks of wood are near the #2 mounting hole. I loosely put the mounting bolts & rubber pads into the front 2 holes to secure the cab to the frame. Then I used a jack & block of wood on each end of the jack to slightly spread the opening, then bolted the cab down to the frame, then put the 3 screws back where I removed them. I did driver side first, then passenger side. Don't think it matters where you start though. Now my sills & doors fit properly. I can email pics if you need them.
Last edited by Charles in CA; 06/13/2012 3:20 PM.