Moose,
Sorry, I wasn’t clear, this is a bush truck so will be driven off-road primarily. Here wood is cut mostly in the winter when the ground is frozen. The rest of the year, if not timed well, the trails can be soft. Patches of bog and thixotropic clay can catch you out and there is also the damage done to the trail that will quickly turn an access trail into a river. Forestry tractors with 4wd usually have a locking back axle to minimize trail damage.
The 411’s on the other hand were originally equipped with only the option to lock both axles. Is there a reason for this? Could it cause damage by only locking the rear? It’s a quick and easy fix to add two more valves for the actuators, but it could be expensive if it blows an expensive component.
The manuals don’t cover the axle/chassis clearance but as Brian pointed out, getting it wrong could damage the torque tubes. With hybrid like mine, it’s hard to guess what’s going to be a solution and what’s going to cause an expensive problem.
Cheers,
Tom