Hello, what could have happened is that if water I mix and work with the oil, it is emulsible and becomes gredoso or as they say here it puts itself as arequipe, if this reached to pass this emulcion, cover the galleries of the hydraulic control that are small communications of oil pressure inside the box, the rod is because the pressure that accumulates must be except for somewhere Rod, what you should do is flushing or pressure cleaning with a special tool, or disassembling the box and cleaning it integrally