my tractor jerks forward when i shut it off and start up?

[mogman770]

my tractor is a hst hydro and when i take it down hills it doesnt want to stop when i take my foot off the forward pedal and when i start it sometimes it shots forward and when i shut it off it will crank forward.. very dangerous anyone know if one of the valves arent working correctly? anything I can check before i go thru the garage.

 

[kenMG42]

Shifting into neutral before shutdown?

 

[ptsg]

That looks like something loose in the pedal's linkage to the HST pump. When you start and stop the engine, it makes that bump that may move the linkage if it's loose. Have you checked that?