Whining hydro lift AC 916

[Mike]

My hydro lift pump has recently starting whining on my AC916. Lift also working a little slower. The hydro fluid appears to be full. Any help will be greatly appreciated. Mike

[Al]

Hi, I would check a couple of things. First I would check the hydro filter. If it is plugged or partially so it can cause this problem. Next if it is an older version with the filter between the frame plates I would look at the hoses to the filter to see that none are kinked or collapsed. next I would look at the steel lines and lines to the valve body and cylinder look for a kink that would restrict the flow. If none of the above are the problem, I would suspect the charge pump. Normally if the charge pump is bad the transmission won't move when you start it and then when the pump gets primed and pressurizes the case it will lunge, if lever is in a move position. If the charge pump is getting weak, it could still be bad. See if you can have a dealer or hydraulic shop check the pressure. If the filter fixes it, cut it open and if it has a bunch of metal shavings if it does, open the rear end up and see what is grinding, as the lower gear case is the reservoir that it pumps from. These Sunstrand units are really tough and nearly bullet proof. The only thing they won't stand is towing. Tow one 3 or 400 feet and and it costs about 3 or 4 dollars a foot. On a new tractor if the hydraulic motor is chewed up there is NO warranty, as the only thing that can cause that is TOWING. When the input shaft is not turning, the charge pump is not running and the upper case has no oil. The rear wheels turn the hydraulic motor and with no oil and it just grinds it up the motor. In 20 years I have only replaced 3 charge pumps, and have only had about 5 of these hydros apart and 4 were caused by towing. Good luck, let us know what you find. Al E.