While 'wondering', take some time to visit the Augusta plant, and hopefully get an opportunity to talk with the engineers there who have, for a good 10 years, been designing the 4000 series, then the 4x10 series, and now the 2000, 3x20 and 4x20 series. /forums/images/graemlins/wink.gif
Probably, what worked back when the tractors were mostly Yanmar still resides in todays design. But then, not much different 'design' from the old 2N Fords in the modern array of CUTs that we see with the many different brand names.
But, not much Yanmar in these other than the power plant. And it's a darn good one.