I even thought about putting one of the expandable boxes on the M36a2 / 2.5 ton, before I went with the shiping container sides. I loved the extra room with the slide outs I think almost 12' wide if I am correct. My neibor has freind still in the USMC and said a few of the M36's had them on the back, but the weight was around 8500 lbs for the box. Just a litlle too much weight for me. But after my current build I might need to start another, if the wife gives me permission.