Very nice model and neat machining, congratulations. It looks very scale, you have been able to fit everything inside the cab! I haven't seen a steering setup like this until now, it is one of a kind.
I hope you are still around as I have a couple of questions, and I hope I get to hear back from you on those. They are as follows
1. Does the front axle articulate, if not, do the rear axles articulate, in other words, how do you manage to keep all 6 wheels on the ground?
2. How do you like the current gear ratio, is it high, low or just right?
3. Where can one find the gear box that you have used, did it come with the pager motor?
4. What U-joints are they?
5. Do you have and make or part number of the bevel gears?