This may/not work on yours, but on real cold days I leave my Case 580SE bucket high in the air when I park it. Then when cranking I ease the bucket down and it seems to unload the pump so that the engine spins faster to crank. I have read where some say this is bad advice, but try it at least once. I would first simply take both batteries to O'Relli or any place that can load test them. If they test good, then take t
Discuss this in the forum topic JD 310C hyd pump question.