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mike, Technician
Category: Heavy Equipment
Satisfied Customers: 112
Experience:  certified master tech 20+ years combines, row crop, and four wheel drive
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I have a 4430 jd tractor with a hydraulic problem The 3 point

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I have a 4430 jd tractor with a hydraulic problem The 3 point hitch arms take a long time to come up ,steering wheel will not turn when first started,hydraulics will not run an external pump pto seems to run fine All this happens at an idle When reved up they seem to work fine   After the oil gets hot every thing slows right down The front hydraulic pump squeals from idle to half throttle The oil lite will come on at an idle after the oil is hot What is the problem?

Hi, the squall in your hydraulic pump is cavitation{ no oil coming from your charge/ transmission pump} or aeration { air being introduced into the charge pressure oil} under your rockshaft { 3 point hitch} there is a pump driven by a 6 sided shaft that receives its power from your flywheel. This pump supplies oil to your main hydraulic pump.Before your selective control valve or your hitch can work there must be at least 1800psi supplied to your steering and brakes. This is where your pressure control valve or as sometimes called your priority valve comes into the system. After there is 1800 psi supplied to steering and brakes it lets hydraulic oil flow to the rockshaft control valve housing for your hitch and selective control valves.


With that being said we know we have a charge/ transmission pump problem. Here are a few things that could possibly be the problem. Screen plugged in differential housing, cracked oil pipe in the charge pump circuit,worn out charge pump, charge pump drive shaft{ the 6 sided shaft, behind a plug, under the top link in the differential housing} plugged hydraulic filter and an internal leak in the clutch valve housing. An internal hydraulic leak in any of these systems will cause the oil to heat fast. This will decrease the hydraulic flow which decreases the hydraulic pressure { slow or no steering, lift chatters or slow to raise no hydraulics and the light comes on}


you could drain the hydraulic oil and check the screen. If it is plugged with fibers or metal shavings then you must determine where these shavings or fibers came from. Because if you just clean it off it will only be a temporary fix. The hydraulic pump that has a squall is probably damaged also, it will need to be inspected. I would take the tractor to your local dealer or repair shop and have it repaired. Operating this tractor under these conditions will ruin the hydraulic pump beyond repair.



I hope this helped, if you decide you would like to do some hydraulic test to pinpoint the problem I would be more than happy to assist you.



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