Jumpy lift on my 9540

[macintosh]

While travelling on the road with an implement raised on the 3 point linkage of my 9540, all is going well until the lift starts to jump violently. It's happened a couple of times and I've had to stop the tractor to avoid being bounced off the road. Could anyone help me with this problem?

 

[Renze]

Replace the lift cylinder seals. My neighbours Deutz D25 has it, the lift leuks down as fast as the pump can restore lift, which starts a nasty wave effect when driving on the road with a heavy loaded 4pt