My Cat 320l has problems with hyd's. Very low power on tracks. Will not rotate itself unless you pickup with the stick. 2spd works. Will move both directions in low and high. High side if you travel over a clod it will stop moving. Recently having trouble with hyd overheating. After 3hrs power drops off. Not motor wise. Any kind of incline in low side, requires pulling with stick. Digging power doesn't drop much. Hyd pressure switch does change power levels. Auto throttle doesn't respond like it should. Haven't tested hyd pressure yet. Test gauges ordered.
How many hours? Serial number? If it fits fine, first guesses are swivel, track motors, or both.
9kk01335. 10500hrs
Regarding the overheating it's common to have to remove & disassemble the complete cooling package from the machine in order to clean it. External cleaning will not be enough. Also there are baffles (sponge rubber strips) surrounding the cooling pack to direct all the air through it. If they are damaged/missing the cooling efficiency will be significantly reduced.
Any luck with this problem? I have a cat 320L prefix 9KK with the same issue.