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7700 Hydrostat

1401 Views 1 Reply 2 Participants Last post by  xp12300
I'm having a problem with the hydrostat on my 7700 combine. When I take off from a
dead stop in 3rd and 4th gear, the hydrostat seems to jerk alittle or slip, but then gathers
speed and works fine. As long as I don't stop, everything is ok. I got my hydraulic
pressure gauges and checked the charge pump pressure, it's supposed to be 180-220psi.
Mine only showed 170psi.
When I checked the pressure on the forward high pressure side, I only got 4100psi where
I should've gotten 5300psi. I then took the high pressure relief valve out and cleaned
it(althought it didn't look dity). I reinstalled it and still got the same readings.
So now I'm wondering if the high pressure relief valve is bad or does the hydrostat need to
be rebuilt?
Does anyone have any experience with hydrostats?
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Re: 7700 Hydrostatic

Is you belt tight it maybe slipping, did you check the reverse oil pressure, you could change the forward and reverse relief valves to see if it helps.
1 - 2 of 2 Posts
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