That's very interesting! I remember seeing a few pages in the 406 shop manual about hydrostatic drive but didn't pay any attention to it. I never understood why a hydraulic *motor* would be connected to the bottom PTO instead of a pump. What it *looks* like they've implemented in the 406 is a similar function if I understand it correctly. Here's how things seem to function if I can detect what's going on from the photos in the manual. First, there is a variable displacement hydrostatic piston pump that looks like it's driven by the rear PTO output - engage the pto and you drive the pump. Next, there's a hydraulic piston MOTOR attached to the bottom PTO where the optional backhoe PUMP is normally installed. So it appears that they're using one PTO out put to drive a pump which powers a motor as input to another PTO to drive the transmission instead of the engine. This way you could have infinitely variable vehicle (low) speed at constant engine speed. Any thoughts? Am I out in the weeds on this?
It looks like you've got a similar system in essence in the 424 with both a hydrostatic variable piston pump and piston motor shown in the picture. I'm not familiar enough with the SBU transmissions to tell what these might be connected to however.
It looks like you've got a similar system in essence in the 424 with both a hydrostatic variable piston pump and piston motor shown in the picture. I'm not familiar enough with the SBU transmissions to tell what these might be connected to however.
