Yesterday, after loading up my bucket with 5-6 loads of 3/4 minus, I started to get some pump chatter (cavitation?) I noticed that my return line (low pressure) was twisting and reduced a little in diameter due to air/diminished flow (?) More importantly, my return line has some excess and had a pretty good belly in it from not being routed correctly so today I am going to reroute to get it level and remove that belly which should help. I have new universal hydraulic fluid in this system which should be fine vs ATF or 30 weight motor oil (it's a 70's machine). Yesterday's experience prompted me to think about pump rebuilding/replacement if this ever comes to be. Are these little kubota pumps rebuildable/replaceable or is there a better update for these pumps that works?