I am having a problem for some time now with my Kubota BH77 backhoe. The swing from side to side is losing power and stopping and starting. I can swing the boom from side to side free hand by holding the stick hard over and it moves freely. Ive done a lot of testing and it seems like it maybe pressure release problem. The control valve for the swing has two control release valves. One on top and one on the bottom. Im confused as to what each one does and which one releases for what each function. Has anyone experienced this type of problem. Thanks