I have seen them in pics before the look like a 4 x 4 coupling on the Jinmas,send any pics you may have with the spline count.They are listed in the parts book under hydraulics DP (Double pump) according to my china supplier they have been discontinued and no parts are avaliable
Tommy
Affordable Tractor Sales Co
“Your Jinma Parts Superstore”
http://www.affordabletractorsalesco.com