Thanks, I have 3 of the Kaelble trucks. They're about 50 pounds fully completed. I've been working on making the rear axles functional on the third; it as well as my second was sold as a display version meaning the frame, cab and, basic suspension but no power, transmission or functional axles in fact no running gear at all. The axles are unusual as one one side is driven normally- left wheel pair on the first, right wheel pair on second or rearmost axle. There is a locker to engage both sides and the wheels are driven through a planetary gear. All the guts are what I've been building out.
I have a reasonable machine shop with smaller machines and I do my own foundry work.
Some of my other projects:
Jerry
http://tanks.linite.com