specking a new truck

[Hammerhead]

10-4! Stick with the 46's then. You answered the only answer that I could think of to justify the question for your application. Just don't break a 46, they are WAY more $$ to fix than a 40!
I've been to Solar Turbine in SD quite a few times and kinda wondered about the whole mud tracking thing, since I've never seen it there and assumed it was that way. Actually, I have a buddy loading there Tues.
I never needed a whole diff when I was there, but I didn't like the wear pattern on one of the bearings when I looked at it which was why they got changed. When they didn't have bearing for 46's I was quite stunned, which lead me to ask the question of availability. I'm naturally curious why people do things differently and I'm always interested to see if I can find a better or alternative way.
I wouldn't run 85psi in 315's, I don't think they are bigger enough to run that low, but I'm not in your application, so take my opinion with a grain of salt.
I understand your outlook of Hendrickson, and Neway is a fine option. Since you have the stated "can't work in the mud" option traction is not as much of a factor as it would be in other locations.