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Message: <blockquote data-quote="Mike10" data-source="post: 100483" data-attributes="member: 5461"><p>Since the boom and bucket stop working, the only common part between the hydraulics and the hydrostats is the hydraulic pump. So you can eliminate anything in the hydrostat circuit. On early model 555s the oil pickup point was right behind the large gear in the chain case. It was possible that the rotation of the gear would interfer with the oil flow. On later models an angled extension was added to the cross tube so oil could be picked up away from the gear. That was just a momentary problem. For the light to remain on for a minute, the hyd pump is not picking up prime. A good start would be to remove the hydraulic pump and reseal it or if it is worn then replace it. I do not think it is the relief valve in the control valve since that oil still goes back to the charge check valve. Even with the relief valve open the oil is flowing from the pump. The oil has to go somewhere and oil the oil that enters the control valve flows out the same port whether from the cylinders or from an open relief valve. This oil then goes to the charge check valve where the oil has to reach a certain pressure before it can flow back to the chaincase, so if the pump is working there should be charge pressure and the light should be out.</p></blockquote><p></p>