I bought a 4755 a few months ago. When I brought him home everything worked. Now the 3 point hitch has stopped working. It has been getting progressively worse. It behaved strangely once when I started it. It took a while but finally got going. Then the other day when it was really cold I couldn’t get him to do anything. When the heat came, I put it in gear to move it and the 3-point hitch kicked into gear but stayed stationary. So he didn’t want to go down, I thought maybe because he had no weight on him. I put the lever down and pushed on it manually and it got off. Now it does nothing. I have played with the draft control. I have tried all the buttons and switches. If you pull the dipstick on the back it says it could use a little oil but it is not low in any way. So some questions I have like this is my first green tractor and I have no manual. What kind of oil goes in the back there. Is that the dipstick to check all the hydraulic oil or just the rear. I seem to be able to hear a cavitation sound from the hydraulic pump, but the other hydraulics seem fine, but I haven’t connected them to anything. Power steering works fine. Does anyone have a starting point? What is there to look at, etc.? I know there has to be some electrical sensors somewhere that does since it works sometimes and not others. I imagine that if it is a hydraulic problem it would never work …..
The dipstick under the rear of the cab checks the rear / transmission compartment which is also used for the hydraulics.
There is a gear pump behind the transmission control valve that sucks the oil from the transmission crankcase and passes it through a tubular screen that can be cleaned by removing a plug on the left side of the transmission normally.
The gear pump pumps through the front filter to feed the lubrication circuit of the transmission and clutch (s), etc., and most of its output goes forward to supply oil to the radial piston pump, from closed center, located at the front. This pump builds up to standby pressure if possible and then shuts down to keep the system on standby. All oil pumped forward to the foreline pump that is not supplied to / demanded by the high pressure hydraulic system flows through the oil cooler or directly back to the transmission crankcase, depending on the oil temperature.
High-pressure oil flows from the foreline pump through a priority valve that powers the steering and brakes before meeting any other hydraulic demands and then powers whatever hydraulic functions are activated.
Rocker lift and draft are electronically controlled on that tractor. It uses potentiometers and a dedicated computer to detect pull and hitch position to control implement depth and pull. There is a test procedure that uses the light and turn signal switch to navigate through various menus on computers to calibrate the response of the lift and lower solenoid valves to the potentiometer inputs. The dealer should be able to print this for you or send someone to diagnose the problem if you need it.
That said, our 4955 does not typically raise the 3-point hitch arms after starting, unless the control lever is pushed forward to the lower position and then pulled back to the desired height position. Cold oil will certainly affect how fast everything moves. Part of the hitch check procedure is to make sure the oil is warm before proceeding.
Check the same the wires to the up and down solenoids were rubbed not through and shorted.