I have a bobcat 753 with an issue with the aux hydraulics. I ran this machine as a kid and it always had the same problem but since i now own it i would like to fix it. in order to do anything with the machine you need to press the aux button below the boss read out twice. Does not matter if your just driving around or want to use the actual hydraulic ports on the front. If you don't press them the hydraulics bog way down and you can hear the motor struggling. Today i went out and unplugged the rear valve on the control valve body and it made the engine not strain and run normal. Would this be a bad valve or something else?