Hi forum members and experts! I own a Volvo EC55B Pro with about 5k hours on it. Love the machine, but I have a problem with it, and I could do with some troubleshooting hints & tips. When moving straight forward (or backwards) there is a hissing sound from the hydraulics. This only happens when both drive motors are running simultaneously. When lifting up either side and running only one motor there is no hissing sound. I have noticed that driving a bit slow, but if I work the boom, stick or bucket while driving it seems to run normal. Lately I have noticed that the swing is quite jerky too, however, if I use any other hydraulic function while swinging, action is smooth and normal. Where do I start looking?
I'd get an infrared temp gun and start looking for sources of heat at the control valve. I believe that has a multi section valve with tie-rods holding it together. I'm not terribly sharp with the minis but I'll share what's available to me.