Ok. The oil did not become overfull when i changed the oil. I did however drain the oil from the side, not realizing there was also a bottom drain plug. I have since then drained the oil a second time, removing both plugs and letting it drain all night long. I tipped it this way and that way trying to get ALL the old oil out. Once i put the plugs back in and refilled it with oil, the oil is staying clean. The pressure is still low but I wonder if i have another problem somewhere. The pressure gauge goes OVER 4,000 PSI when the trigger is released and the unloader goes into bypass mode but when i pull the trigger, sometimes it says 3,000 psi on the gauge and sometimes it says 2500. This is with a size 4 nozzle which is correct for a 4000psi 4gpm machine. There are no unusual vibrations in the hose (which i have seen with worn seals in other pumps before) and no leaks. I used a timer and timed 60 seconds while filling a 5 gallon bucket with the gun and it got what seems to be a little over 4 gallons in that 60 second time so it has not lost any volume. I really kinda think that everything is fine and that maybe its the gauge reading wrong, but then again it does show 4000+ when i let up on the trigger so who knows. Anyone got any ideas?