The 4k series were used on the MRAPs, and are starting to hit the government auction's. I originally wanted to go with rocks, but I didnt want the toploaders as I would be higher than I wanted, remember, I want low cog. Front load rocks exist, but finding a set available for purchase was non existent. Then I looked at 5 tons, same thing, I didnt find any available. So I started looking at planetaries, and these seemed like what I want. Best part is, they come with any gear ratio from about 4:1 all the way to 13.74:1, come with air lockers, hydraulic disc brakes, some have central tire inflation built in, all already in one package. A big plus is the front load pinion, the planetaries are about 2" past the wheel mount surface which means no hubs sticking out to break off, and the best part is the 35 spline axle shafts. This may not sound big for a 9 ton axle, but remember the planetaries are 4+ to one, which is comparable to a 6" diameter shaft with 140 spline count
SVT