Did it and it's worked for me for years. Used the hard to find rear output PTO and moved the stock dump-bed pump over to the left hand side by fabbing some plates that took hydraulic hoses and hung the pump on the frame. The M35 frame had to be shortened a bit so the dump bed could do it's vertical dump thing, really handy w clay, wet stuff, etc... Yes, the 5 ton bed is heavy but it's also tough. never a bad thing for a woodland dump truck. My avatar is a pic of this very rig...
Seven or eight years later the only problem has been the stock rear springs have sagged a bit but not enough to create an issue. If I had any get up and go anymore I'd rebuild the spring packs and add a few leafs, have new U-bolts bent up, etc... I've learned that tired and dry-rotted dog-bones will cause you some grief in off-road dump truck operations with lots of suspension travel. The stock tires have little sidewall strength so be careful around rocks and debris, I put a lot of dolomite into wet areas for access roads, it doesn't take much of a chunk left on the approach to ruin a tire when loaded. When in the woods I tend to stay in low-range but I use the transfer case range to get going otherwise, starting in low range & then shifting TC up and dropping back on the trans kinda like a semi.
And when you get stuck USE THE BLOCK WHEN WINCHING!!!
