Never knew about a bearing in the seat, so you're saying if you had a choice you'd just get a 5 ton?
Yeah, there's mention about it in the LO, the TM, and some posts here about maintaining it. My understanding is that you can go a few thousand miles between PMCS with it though, like everything else on the truck (the LO says to check bearing nut tightness and lubricate every 3000 miles).
I was originally looking for an M813 but knowing what I know now an M923 with full air brakes is how I'd go - I value stopping too much now to settle for anything less! Of course some of the parts, like brake drums, are going to be heavier, and you might need a CDL to legally drive a 5-ton depending on your state's laws. Another bonus with the 5-tons is that they all come with hydraulic power steering.
I just looked in the M939 LO and it says to check the rear suspension spring seat/trunnion bearing like on the deuce, but the repacking interval is twice that of the deuce (12000 miles vs. 6000 miles). However I've never heard of a trunnion or bearing failure on that part of any 5-ton.
After all that you might be wondering why I went with the deuce anyway. I did it because at the time I recently sold a Ford 1803 tractor I inherited because I was moving soon and had no use for it at my new home. However I wanted to replace it with an old military truck instead of the money being spent on something else and formally make my own entrance into the hobby after having done it with my dad and his trucks for years. I also wanted a truck with some cargo space that could help with the move. Any 5-tons I found were far away and I couldn't take the time off to look at them, or some closer by were out of my price range.
One of my dad's friends was local and gave me a sweet deal on an M35A3 that I was able to look over and test drive. I really liked it and bought it. As soon as I put plates on it, I brought it home and moved two trip's worth of storage bins and a single trip of my kids' outdoor playground equipment to my new home. Despite its quirks it's been a fun truck to drive! I guess part of it is considering that I have a desk job that I can talk about how I work on a big truck with big tools - all for "fun"
(Okay yeah it is kinda fun!)
So I guess I should clarify: If I had more time before my move, I would've waited longer for the right 5-ton. Instead I bought the right 2 1/2-ton