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Eastern Iowa | I'm starting this thread over, the first one is on page 3 now.
I have a 4430 Quadrange. It has a loader on it and the front pump has been cavitating when I start the tractor. We put the tractor on the MoCo the other day and after an hour or so the tractor lost hydraulic function. The driver unhooked the MoCo and was able to get the tractor home. We drained the oil, replaced the filter and checked the screen, it was clean. I cut the filter apart and found nothing to obvious. It sounded to me like a trans pump problem so I pulled out the trans pump hex drive shaft and it looked very good. Next I plumbed into the filter relief valve housing where oil flows out to the pressure control valve. We ran the tractor and filled a 5 gallon bucket in 30 seconds while varying the pressure with a ball valve. The flow remained consistent at various pressures. Next I put a hose gauge and valve on the high pressure manifold (square block on right side of trans case) I plumbed into the exit fitting after the manifold. There I had erratic flow and was unable to build pressure unless the valve was almost closed. If I closed the ball valve It would build pressure to about 2000 psi. From there I went to the output line on the pressure control valve (left side of clutch housing). I removed the line that goes between the pressure control valve and the main high pressure front pump and plumbed my gauge and valve in there. I had very poor flow, just a gallon or so in 30 seconds with no restriction and less when I restricted the flow. In the first thread KelB instructed me to put a gauge to the test fitting on the filter relief housing and not the rpm when got 10 psi. I got 10 psi at wide open throttle, (2500 rpm) and it dropped as the oil warmed. I activated the pto and pto brake as instructed and saw only a momentary change in pressure. I also operated the quad hi/lo and saw only a momentary fluctuation. by now the oil was heating and I was only running about 3 psi at 2500 rpm. Any ideas what I should do next, I'm not seeing where my problem is. I would buy a tech manual but they have to be ordered and I need it now. Yes that is also what I said 8 years ago when I had the whole thing torn apart. | |
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4430 hydraulic system troubleshooting
