"..If the metering pump is fine, then it has to be the valve under the hood, right?.." Somewhere between probably and maybe. Here's a few things you need to know about the metering pump steering system: When you turn the wheel, all you are really doing is cranking a little gear pump that pushes a spool in the steering valve from one side to the other. There isn't supposed to be any super high pressure oil in the metering pump...Unless the spool has lost it's very close metal to metal sealing with the steering valve housing. When 30 years of grit wears this close fit away, leakage through the valve into the pump increases, the pressures rise, and those darned hoses want to blow off. "..when you get back in the steering wheel is chattering.." Uh, oh. Take a look at the ticket you got from the Deere dealer. Make sure you got billed for one AR88771 check valve. The "outlet" fitting on the metering pump has a check valve built inside. It LOOKS just like the other three fittings on the outside. {you said they did away with the hose barb fittings. AR88771 is the number for the screw on check fitting. You should also have been billed for only ONE R68220 plain screw on fitting.} If the check valve isn't working, {or left out} it causes the steering wheel to shift up and down. You may not be done with the pump just yet. "The screen on the valve had a lot of metal shavings on it.." Take the screen back out. If you get another valve, don't trust the screen in it, either. I have seen lots of dirty steering valve inlet screens. If they have very much visible stuff on them, the screens are ALWAYS ruptured. Poke the screen {gently} in each section, especially near the closed end. I'll bet you find a section that is no longer attached to the black plastic. Get a new one. This might be the reason the steering valve died. I see this a lot. Someone spends big $$$ on a new valve and then kill it right away with a screen that is blown. {Most don't even know there is one in that weird looking fitting.} One more thing about "remanufactured" steering valves. Remember that part about the spool to housing fit being a very tight metal to metal seal? How does someone "remanufacture" a component that is built like this? Do they bore the old brick out and custom make a new oversize spool and fit it carefully?? The answer is NO And I would bet on it. What you are buying for $500 is a salvaged valve that has had the grease scraped off and painted. If you are lucky, they might have given you the first class treatment and actually looked at it internally and put some new o-rings on the fittings. But "remanufactured" ?...Please. How dumb do they think their customers are? If the used valve is in good shape, it might barely be worth $500, because a new one from Deere is over $800. I'm rambling now, so here's what I would do if I were you. Take your valve off. Clean the outside real good. Check out the screen closely like I mentioned. Don't squeeze the valve too hard in the vise and unscrew the two big plugs on the ends. The spool should slide out with finger pressure. See if the surface of the spool has scratches deep enough to feel. {Bad} If everything slides smooth and looks OK, there is a spring between two check balls inside the spool. Make sure something small isn't jammed between a ball and it's seat. {something like a chunk from the steering motor piston seals, if you are unlucky} If the spool is rough? Sure, you could take some lapping compound and some sweat and MAKE it smooth..But you won't cure the problem of excess oil leakage past the valve. In that case, you'll need another valve assembly.
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