Hello Ron here are some details.
Total cost is less than $2k. Most of that is in the hydraulics. The most expensive part is the control spools and the hydrualic motors. The system is completely hydrostatic drive. So it uses hydraulic motors, one per side and drives just like a tank would.
The engine is a 75 Pinto engine. I bought a pinto from a local impound yard for $50 bucks, another 50 for various things the engine needed. The pump is rated at 3500 rpm, 3000 PSI, and puts out 14 GPH at 2000 RPMs. However, I designed the system with open centers on the spools. So, if you are doing no work there is no pressure in the system it bypasses. When you close the spools for driving or lifting you only develop enough pressure to do the work so it is nice to not have 2k psi all the time.
I also fixed the problem that so many skid loaders have when driving. Many skids will jump and jerk as you move the controls around. I simply put a needle valve accross the motors and set it for about 10% total flow. This will then give you a bypass for small variations in the control and also gives a nice braking action if you let go of the controls.
I have more details but I dont want to bore you too much
chrisk
