3-Point Hitch Shudder on descent

[kpmcneil]

1963 fordson super major 5000. When I lower an implement with 3ph there is a distinct and pronounced shudder as it descends. Not an issue when raising, but I can't seem to set a constant draft angle, implement will raise at times without moving control. What part of the hydraulic guts should I look at first.

 

[RayIN]

consider making a set of check-chains to limit cutting height. I did that with my old H.Ferguson 30, it would not maintain set height either. I used an extra long top link pin in the tractor and made ends for the check-chains with a 3/4" hole, then ran the chains down to each lower pin on the mower; an A-type configuration. It took a few tries to find the correct chain length.
EDIT/UPDATE: I just discovered this is available as a kit.