Des, I assume you are referring to the drive plumbing. I've attached a drawing of the basic circuit. The front and rear axles are in series, the 2 motors on each axle in parallel. The idea being that there will always be power to one of the wheels on each axle.
We thought of some ideas for making it transfer power to the wheel on each axle with most grip, could be done so that it does it automatically, but I'm liking the simple idea of replacing one of the T's on each axle (where the spots are) with a 3 way diverter, that way you can just push the lever towards the wheel with the most grip and bias the flow/pressure towards that wheel.
I guess the same effect could be done with relief valves and check valves, but I like the simple but effective idea of using 2 manual diverter valves, one for each axle.
99% of the time they would be in the middle providing the same flow to each wheel, but you would just adjust it as you would use a diff lock to climb out of tricky situation.
Nica, I'll keep track of the time here, that'll be the easiest way. If we include design time I'll reckon I'm 50 hours in to date.
Cheers guys