Oil & Fuel Hydraulic Fluid Change

[lmike51b]

I have a 1992 JD 770 with hydrostatic power steering. It has about 1950 hours, and since I知 not sure if the hydraulic fluid has ever been changed, I need to change it. The operator manual refers to draining the fluid from under the tractor, removing 3-4 bolts to remove and clean the screen, and if the tractor has power steering removing and replacing the filter. But does this also drain the fluid from the power steering pump? Does the pump need to be refilled?

 

[5030]

Not sure bur with that many hours, I'd for sure do an oil analysis on the drained fluid. I change mine every 1000 hours. Mine takes 47 quarts.

 

[dirt ditch]

My JD 790 with power steering uses the same hydraulic pump as your 770 (JD part #AM876753). The tractor holds 4 gallons of hydraulic fluid. Don't mess with the pump, what little oil does not drain out of the pump is not worth worrying about when your replacing 4 gallons of fluid. Just follow the instructions in your owners manual and replace the hydraulic filter when you clean the screen and change fluid. JD recommends Low-Viscosity Hy-Gard for for these tractors.

This thread should help you out.

http://www.tractorbynet.com forums - john deere owning/operating - about changing hyd tranny fluid on a 790