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I have a 5120 maxxum tractor. It has been very good but is starting to have some hydraulic issues. Tractor has 9800 hours so I’m aware it could be the pump but I have read there are a few other valves that can also cause issues. The tractor is intermittently having the issues sometimes it sounds and operates okay other times the hydraulic pump sounds kind of growly and loud like it’s sucking air. It comes out of gear once in awhile especially when using the loader, but you just dab the clutch and your off again. The loader is slow and kinda loud but I lifter a 6 row buffalo cultivator off the trailer yesterday that weighed 3-4000 lbs and it did that fine. Any ideas or things to try would be greatly appreciated
 

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Does the transmission disengage when you turn the steering all the way right or left and hold it there?
 

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Doesn’t seem to be the case it’s almost like it over works something in the system trying to move forward turn and raise the loader. I took the loader off tonight and drained the hydraulic fluid. Fluid looked good. I took out the suction screen and it had some stuff in it but was still 90% open I would guess. There are a couple we hoses I may try and replace and put it back together and try it. I’m wondering if it’s sucking air somewhere
 

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Does the oil get hot after a while. If it’s seems to be working when doing nothing I’d check to see if the functions for the loader and hydraulics are working as they should. Sucking air would give you jerky or shuddering hydraulics. Is there a filter that would be catching smaller particles after the screen. You say there is stuff in there but how much is too small for that to stop. Check pressure relief valve and that the controls actually return to a stop position after operation.
 

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Does the transmission disengage when you turn the steering all the way right or left and hold it there?
Whats the significance of this?
I've been having hyd issues as well lately, 5240 model. Dont even have to turn it all the way for the clutch to disengage while drving forward or reverse. Remotes and 3pth are very slow too. When shifting forward or reverse with the shuttle shift, its like you are popping the clutch, no delay at all.

Funny thing is the steering and remotes work OK when its revved up, even a little.

OP- did you ever find out your problem?
 

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Would still like to hear from someone who can explain the significance of clutch disengage when steering wheel turns.

I had a guy out to test it a week ago, said my hyd pump behind the battery was gone. New pump on it this morning (6000$ later) and no improvement, still the same. If anyone has any ideas?
 

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I don't work on these tractors but I will take a shot. Likely the clutch disengages because steering is priority and there is not enough oil left over to keep the clutch packs supplied this could be from various reasons. Was the guy you had out from the dealership and what tests did he do? First test should be to check the steering relief pressure which should be set at 300 psi below high pressure standby. Next thing to check would be the signal line going to the hydraulic remotes, remove the line going to the remotes at the T and cap the T leave the end going to the steering hooked up and drive tractor if everything works there is likely a leak or bad check valve in the signal line going to the remotes and three point. Being as you replaced the hydraulic pump that kind of removes it from the system I would just check to make sure high pressure standby and low pressure standby are set correctly. Then comes the regulated pressure check which I have not done on these tractors but it will check for any leaky seals in the MFD, PTO, Diff lock and any other circuits tied to the regulated circuit. The last thing on the list is the safety jump spool however I don't know what it does or where it is I will have to look into that one. I would think your dealer would give you access to these test sheets so you could preform them. If your dealer did the work they have access to them and should have checked all this before replacing the pump.
 

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So long story short set high pressure standby and low pressure standby on new pump, set steering relief pressure, after that there is likely a leak in the signal line circuit telling the pump to go to work or the regulated pressure circuit.
 

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thanks so much for your insight. guy i had out was an independent guy who knows these tractors; my dad had used him before. we usually do our own repairs but we didnt have all the fittings and guages to do the testing as explained in our service manual. only thing he did was test remote pressure and then hooked up a flow meter to them, to check the charge pressure i believe he said?? i was in the cab turning the wheel and pulliing the remote lever so didnt really see what he was doing. he seemed very confident the pump was the issue so here we are. i will order some fittings and do the tests you described.
 
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