Originally Posted by GMLC
Lets try to get back to the OP's problem here. IMO the long wheel base is beating him to death like being on a seesaw. The rear tires almost come off the ground a few times in those videos. In this case I feel a shorter wheel base mower would be better like his old mowers that do the same property with no problems.
Long wheel base, short wheel base, it really makes no difference, on a property such as this you slow down to a point where you can ride the highs and lows like a boat going up and over a swell.
There is honestly a very simple fix for this problem, when too rough, slow down. I would take bets there is absolutely nothing wrong with the mower.
I have about 1/2 acre with the same problem, except probably a little worse, and I have to slow down to the point of crawling through the ruts, I mean virtually stopping all together, and then easing through each one individually.