# JD 2240 Hydraulic high-pressure loss while operating



## jay-young (3 mo ago)

Hello everyone, pull up a good chair and your reading glasses! I tried some other forums with this problem but have not been able to nail-down a solution so I'm bringing my problems here!

I’m working on a late-70’s era JD 2240 tractor with JD loader. It’s been a good problem-free tractor for the past 15+ years while owning it. It gets used around our 100-acre property year-around where it primarily gets used for brush hogging, hauling firewood, and making several hundred bales of hay. It been well maintained and never harshly used while in our possession. On an annual basis, it might see 80-120hrs/yr of use
Over the past several years (2+) while running it in the summer (either brush hogging or making hay) we would experience the power steering and all hydraulic functions stop while just running at a normal operating RPM (2200rpm). We limped through last summer struggling with the issue. When the hydraulics and power steering would stop operating, we would normally shut everything off (tractor included), walk away for about an hour and allow it cool down then it would startup and everything would work for the next hour or two before the hydraulics & PS would drop-out again.
Over the winter we sent it to the shop, they changed all the hydraulic fluid, filters, and screens then ran the tractor outside in the cold for an hour and never experienced the hydraulic pressure or PS drop out. We entered this spring hopeful that the issue had been resolved but after several hours of brush hogging we experienced the same issue. It has gotten to the point where if you’re working it semi-hard, it will go about 500 yards before the losing high hydraulic pressure and you need to disengage the PTO & then the hydraulic pressure will pop back to 2150psi & you can re-start the PTO and go another 500 yards.
Over the past several months, we’ve added two pressure gauges in an attempt to monitor the pressures within the system. I added these gauges to both the high-pressure and low-pressure output ports on the tractor as seen below.












The low-pressure side runs at the expected 130psi and *never* fluctuates or goes to zero
The high-pressure side runs at the expected 2150psi when the engine is cool but:
When the issue occurs, the pressure does drop to 0psi and may bounce around 0-60psi sporadically.
Does not return to the expected 2150psi until:
The tractor is shut off and allowed to cool
I disengage the PTO. When I disengage the PTO, within 2-3 seconds the high-pressure hydraulics and power steering returns.


*Here are the items that I’ve been able to easily check/verify without getting too deep into the system (highlighted in yellow above):*


The intake screen (#10 above) is brand new and clean/clear
I removed the bypass valve (#11 above), it’s clean, spring is good, and it actuates freely
The hydraulic filter (#12 above) has been recently replaced
The hydraulic fluid is full and clean
I’ve read posts about looking for internal hydraulic leaks but removing the fill-hole cap and looking for mist/fog within the chamber. I see none of that while it idles.
*General observations:*


I’ve noticed the steering column (where the power steering is located) get pretty warm to the touch (able to keep your hand on it for 6-8 seconds before needing to remove it) after hours of operation.
Another thing worth noting is as the tractor runs and works the engine RPM drop-off and I’m not able to rev the RPM as high as when it’s cold. Typically, it can be a 300RPM drop-off between warm and cold
*Questions:*


I know this tractor has a “Closed” hydraulic system with no flow occurring when things are in a “neutral” state. If I’m just running the PTO and maybe lifting an implement at the end of the field, aside from very limited power steering demand there should be no meaningful flow in the system the majority of the time right? Why would the fluid be getting too warm to touch in the steering column?
The service manual makes multiple mentions of a “Thermal Relief Valve” but never can I see it shown in any of the diagrams. Where is it located and what happens when the fluid gets too hot, will the high-pressure oil dump back to reservoir? Should I be looking closely at this?
Why when I lose hydraulics and PS if I disengage the PTO does high-pressure hydraulics jump back to 2150psi?
While I haven’t specifically tested this yet, is it possible the drop in hydraulic pressure is tied to loss of engine RPM due to the “Speed Adjust” feature of the Roto-Diesel injector pump?
Where should I be looking & for what?
Thanks in advance for your input.


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## Fedup (Feb 25, 2014)

That's an interesting list, to be sure. You've been elsewhere with it, and no doubt received some thoughts and suggestions. Maybe you could share a few of those, which ones you tried, and what if any results that brought?

Pending that, my first thoughts go to your diagram and the indicated location of the second high pressure gauge. If I'm reading this right, it's tee'd into the line leading to the SCV? Is there a reason for that location other than it may have been the simplest place to tie in? In my experiences on tractors with that system I prefer to tie in closer to the piston pump. The spot shown is downstream from the steering priority valve. My understanding is that valve requires 1750 or so PSI, or little to no flow will get past it. You may have less than the required priority pressure ahead of it, still much more than zero, and you may not know it. I would try to tie in with some custom plumbing around the tee supplying the steering valve. 

About the steering valve. It gets hot after a few hours running. Have you considered investigating for possible internal leaks there?


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## Tx Jim (Jul 28, 2020)

Welcome to the TF
I agree with Fedup what type hyd solutions have you previously received & performed?
1st thing I suggest is operate tractor until hyd's begin to fail then remove supply line from steering valve then cap pressure orifice. Operate tractor to determine if hyd's immediately improve indicating problem is in steering valve with faulty o-rings &/or control valve bodies.
2nd with hyd oil at operating tempo, 3pt raised, engine operating look in open hyd filler hole behind seat for spraying oil. Spraying oil indicates faulty 3 pt control valves &/or valve seals.
What type hyd valve controls FEL(ind or scv)? If ind valve how are valve supply/return hoses connected to tractor hyd system?


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## jay-young (3 mo ago)

Fedup and Tx Jim, 
Thank you both for taking the time to reply and offer-up some suggestions. Truth is, I posted this exact same post on another forum back in May of this year and gotten zero responses . Back in Sept. I tried re-igniting the conversation but again didn't get any responses so in all actuality, you're the first two to response so thanks again for that!

Fedup, 
You're right, my choice in location for the high-pressure gauge was simply out of ease and I agree/understand locating it ahead of the steering priority valve would be more benifical and ideally rule-out the piston pump itself. 

Both Fedup and Tx Jim,
In regards to leaks within the steering pump itself, I've considered trying to bypass the power steering pump to see if continues to do the same thing but working/driving it for hours without power steering would likely be difficult. I wish I had an easy way to measure/see flow through the power steering pump but I can't seem to find anything reasonably priced and easily installed. Any suggestions? Am I correct to assume with no change in steering direction there should be no flow through the pump? As hot as the pump/casting up the steering column is getting, I have to believe there is constant flow after a certain amount of time. I'll look closer at what's involved with what Jim is saying about capping or possibly adding a ball-valve to the input of the power steering pump. If I could get a ball valve installed and was able to cause the problem but then close the ball-valve to the power steering and pressure picked-up again I would have to believe the seals in the PS pump are to blame.

Tx Jim,
Your second suggestion about looking down into the oil reservoir while running, I've done that and never seen any noticable mist or spray indicating flow within the reservior which makes me hopeful that maybe it's not an internal seal within the rear-end of the tractor. Is that a semi-safe assumption until I can rule-out the PS pump?

Thank you both again for the time and suggestions, simply conversing often spurs ideas!
Jay


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## Tx Jim (Jul 28, 2020)

Small correction to your statement: steering component you refer to as a pump is a control valve assembly not a pump. 

Have you removed hyd filter cover then engaged starter for 15 seconds then measure amount of oil in container? There should be about 1-1/4 to 1-1/2 gallons nof oil in container. I think when disconnecting power steering line as a test one could determine in short amount of time if power steering valve is faulty & leaking hyd oil internally.


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## Fedup (Feb 25, 2014)

I've never done this, but it should be possible to remove the cover on the right side below the steering column, start and run the engine for a while with it off and look for oil flow coming down from the column area. If you don't turn the wheel, in theory, there should no flow through the valves, thus no return and no drainage. I think the drain from the valves is on the left side of the column casting, so that is where I suspect you would see oil coming down if the valve O rings are leaking. I would suggest NOT turning the steering wheel at this point since the cover has a support bushing for the crank arm which will not be in place with cover off. 

You will probably need to remove some stuff to get it off, but I think it can be done.


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## Tx Jim (Jul 28, 2020)

Drain for JD utility tractor power steering control valve is at the rear of steering valve housing. Green circle on gasket seals PS housing to clutch housing that has an oil galley back to trans case. I think removing housing on RH side will not reveal PS valve drain area.


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## jay-young (3 mo ago)

Tx Jim & Fedup, 
You've given me some more meaningful tests and diagnostics to try this weekend. I have not tried measuring flow via removal of the main filter but that seems doable. Fedup's suggestion of cracking into the steering valve and monitoring that sounds a bit more risky if there is a bad seal and oil starts flowing immediately, unsecured parts will likely start flying but it may come to having to try that.

Back to a more basic question no one has been able to answer for me: The tractor's service manual talks about a "Thermal Relief Valve" but never shows it in any diagram: 
1) Is there such a thing as a thermal relief valve on this tractor?
2) Where would it be located?
3) Would it remove pressure from even the power steering valve and cause a loss of steering similar to what I'm experiencing?
4) If there is such a thing, I would assume it's mechanically operated, what would malfunction on it a spring?

Thanks again. It will likely be this weekend we I fool with it.


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## Fedup (Feb 25, 2014)

I can't help with any thermal relief valve. Don't recall ever needing to search for one. I've been through a few steering valves, but never one of those.


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## Tx Jim (Jul 28, 2020)

Only thermal relief valve that I'm aware of screws into rockshaft piston housing. One rarely see one fail.. Thermal relief on rockshaft housing is designed to open if hyd oil in rockshaft piston housing pressure gets too high due to high hyd pressure or heat(hence the name thermal). See item 2 in following link. https://partscatalog.deere.com/jdrc/sidebyside/equipment/59573/referrer/navigation/pgId/248612
Capping power steering hyd pressure supply line then operating tractor to monitor hyd performance is IMHO one of the easiest closed-center hyd tests to perform.
Simply disconnect supply line on RH side of tractor under steering valve housing then cap nipple then operate tractor. No oil should escape.
Disconnect line(item 1) then cap nipple on line(item 6) where line was attached.


https://partscatalog.deere.com/jdrc/sidebyside/equipment/59573/referrer/navigation/pgId/252675


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## Busted Tractor (May 22, 2018)

It is normal for hydraulics to get hot, yes hot enough it becomes necessary to move your hand.

A closed center system does not totally shut down all flow. There is always some oil "leaking" past the controls for cooling and lubrication. So a drain line should have minimal oil all the time.

You state the pressure returns when you turn the pto off. That is the first place I would check, the pto clutch or passages that pressurize the clutch, then move on to the pto control valve. Is there a test plug in the pto circuit?

I know little of JD but years ago I was left with a MF 1100 that the pump would not shut down. Started plugging control valves the hydraulics went to. Of course the hardest to get to the steering hand pump (the control at the bottom of the steering wheel) was the leaker. Replaced the hand pump and the system was back to normal, after readjusting some settings other mechanics had adjusted to try and fix it.


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## Tx Jim (Jul 28, 2020)

Busted Tractor
I was taught back when I served for 13 yrs as a JD dealer service manager of the 21 yrs of dealership employment that JD tractor hyd oil temp as a rule shouldn't exceed 100°F + ambient temp. 

If JD closed center hyd is operating correctly the front hyd pump when stand-by pressure(2250 psi) is reached goes out of stroke & front hyd piston pump was designed to STOP PUMPING OIL. In order for frt hyd pump to stop pumping oil the oil is routed into pump crankcase(body)& hyd stand-by pressure pushes the pump pistons away from pump rotating shaft. Therefore it can't pump until pressure drops so springs can push pistons against the rotating pump shaft so pumping oil by frt pump can commence.

Yes trans pump is designed to almost continually pump low pressure oil to lubricate trans & differential. The trans pump role of oil supply is determined by JD tractor model & type of trans.

As I previously stated JD 2240 power steering control is a CONTROL VALVE NOT A PUMP!! Later model JD tractors such as 2750 & my JD 4255 had metering pump to control steering.

As I previously stated I think part of jay-young tractors hyd problem associated with pto is in the PTO BRAKE CIRCUIT not clutch circuit


https://partscatalog.deere.com/jdrc/sidebyside/equipment/59573/referrer/navigation/pgId/231038




https://partscatalog.deere.com/jdrc/sidebyside/equipment/71557/referrer/navigation/pgId/2783925


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## Busted Tractor (May 22, 2018)

Tx Jim said:


> Busted Tractor
> I was taught back when I served for 13 yrs as a JD dealer service manager of the 21 yrs of dealership employment that JD tractor hyd oil temp as a rule shouldn't exceed 100°F + ambient temp.
> 
> If JD closed center hyd is operating correctly the front hyd pump when stand-by pressure(2250 psi) is reached goes out of stroke & front hyd piston pump was designed to STOP PUMPING OIL. In order for frt hyd pump to stop pumping oil the oil is routed into pump crankcase(body)& hyd stand-by pressure pushes the pump pistons away from pump rotating shaft. Therefore it can't pump until pressure drops so springs can push pistons against the rotating pump shaft so pumping oil by frt pump can commence.
> ...


Thank you for getting me up to speed on JD terms. As I said I might not know specifics of JD.

As you pointed out 100*F + ambient may be uncomfortable to put your hand on.

As I was taught by MF and White the pump shuts down to a minimum flow just enough for leakage, to cool and lubricate the hydraulic components. The pump on MF is fed by an open center pump in the center housing. No springs are used to operate the pistons in the radial pump up front. White used an axial pump on the closed center tractors some models were gravity fed and some were pressure fed.

As usual JD has to name parts different JD steering control valve, most other manufacturers called it and steering hand pump, JD selective control valve, most other manufacturers auxiliary control valve. Just two examples.





steering hand pump at DuckDuckGo


DuckDuckGo. Privacy, Simplified.




duckduckgo.com





As for the pto as I said I am not familiar with JD and do understand the brake may use pressure to open it. Logic told me that when the pto stopped was when pressure should be applied to a clutch pack. So that is my reasoning for considering the clutch apply circuit.

If I am to much of a bother please tell me and I will bow out, I am only trying to help, even if I don't know the exact issue.


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## Tx Jim (Jul 28, 2020)

Busted Tractor
It's not my place to tell any poster to "bow out"!
I think previously you have posted some very good & useful information.
I think "all information posted about tractor's/farm equipment should be as correct as possible".

As I previously stated I think JD 2240 PS control valve is very different from a steering pump with totally different type components. See both photos below 1st is for JD 2240(items 19 & 23 are individual steering units) & 2nd photo is steering pump for JD 2750


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## Always something (6 mo ago)

I have been on a salvage run and haven't slept much .
There are so many things I have had trouble with on My 2240 . I am having a hard time even seeing what has been suggested. WAS MINE I would check the suction screen in the pump .Find and check the check valve in the suction line where it come out of the transmission. Check the back flow check valve in the charge tank .I know that isn't what it is called .The little tank in front and at the top of the radiator .There is a steering bleed off line and the small low pressure line from the pump on top of the tank .Pull the bolt .Inch and a quarter.or close .be carefull not to damage the tiny tubes .Use a very clean flexible magnet and fish around in the tank for possible check ball clip and spring (s).It is possible There could be 2
.If you have a clogged pump suction screen reseal the pump. Don't be a dummie like me INPECT THE STROKE CONTROL VALVE AND SEAT RELPACE IF THERE ARE ANY SIGNS OF WARE .however slight it might be .All main pressure in your system is controlled by a single pressure relief valve .Since the pump is a detent pump the pressure relief doesn't have a lot to do.It does however move ,Check it and keep the pressure shim washers well protected .A magnetic bolt tray is a must.It sounds to me like your suction screen is clogged .So resealing the pump should take care of the problem .When the hydrolic filter was changed did you find any odd wayward pieces of metal that might look like a washer?or maybe reassembling A dip stick only thinner and with a slight curve? Your problem sounds like mine .Stop the flow putting the fluid in a neutral state the debress clogging the screens falls away and you have pressure again until the debress is sucked into the screen again.I have lived it 3 times since I bought my 78 in 82.Evey time you check the fluid blow all trash away from the dip stick .Same with adding fluid .Be as clean as possible. clean remotes and keep them capped and plugged .If the Steering pressure test good leave it alone .If you can turn the steering with ease and either raise the lift or operate any hydrlic funtiction at the same time
That Is all the test you need .Remember this the internal charge pump is gear driven, stop the gears stop the pump .By fully depressing the clutch you are stopping that pump
At that point the little reserve tank feeds the main hydrolic pump .But only briefly .So faulty back flow checks are devastating to Constant flow.I hope I said that all right . There things learned in the field that cannot be taught in a service manual..Also hydrlic fluid is going to run close to engine temperature .Transference of heat through the metals that come into contact with the engine are going to get hot .the steering colum Takes presendance over all else so the fluid and heat will go there first .Just comman sense. All I am telling you is from 40 years of working my 2240 hard very hard .As a result parts ware and friction heat buildup like everything else adds up to hot .The average person cannot comprehend it when I say heat tolerance is self taught .Strapping your self to a tractor that runs around 180 degrees takes real heat tolerance. A ] 2240 deere is like riding a hot rock.Wash the radiator often. It is a deere and the harder you work it the better it runs.


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## Tx Jim (Jul 28, 2020)

Always something
[/quote]Remember this the internal charge pump is gear driven, stop the gears stop the pump .By fully depressing the clutch you are stopping that pump[/quote] 

Your statement depends on type of pto that tractor has. IIRC tractors with ind & continuous pto drive trans pump differently & tractors with ind pto power trans pump anytime engine crankshaft is rotating.


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## Always something (6 mo ago)

Tx Jim said:


> Always something


Remember this the internal charge pump is gear driven, stop the gears stop the pump .By fully depressing the clutch you are stopping that pump[/quote]

Your statement depends on type of pto that tractor has. IIRC tractors with ind & continuous pto drive trans pump differently & tractors with ind pto power trans pump anytime engine crankshaft is rotating.
[/QUOTE]

I only am familiar with the one I have .And wondered. as I was saying that if all were like that .I have to fix all of them .I have gone international My neighbor deals in internationals. And I just like old tractors .New is nice but I am low tec .
The 2240 was my first tractor.And my first experance with closed center hydrlics .Not being a deere technician didn't help .Just last last year I went through hydrlic power loss symptoms that sounds exactly like O.P.s I had a almost completely clogged pump suction screen 

Pump check valves broken metal pieces in the main hydrlic filter . Check balls and retainers and springs in the resvior tank .Cold all pressure gage readings were normal.Charge pump flow was strong .So I went through the pump .And because I had hay ruining in the field the stroke control valve kit in setting on my desk. And the only good thing about that is it ain't wearing out.When you buy the pump seal kit from deere it comes with schematic showing seal location .It also comes with screen seals .If check valve (Ball )parts are broken you can oder individualones from deere .I have had multiple issues .all caused by my ignorance .Had worked on fork lifts and hydrilcs and never encountered closed center piston pumps before.And rather than doing research .I almost destroyed my great little tractor. 
By putting a open centered remote on my tractor . Dealer that sold me my 410 baler said just put a after market valve on my tractor .I needed dual remotes 
l Never said it has to be closed center valve.And yes he was a deere dealer .My dealer found me the baler. sent me to him. .Awful just awful expreance .Young ignorant and poor .It was the best little tractor I had ever operated .I have spent thousands because I was ignorant. Now It just pulls my baler.
Runs maybe 40 hours a year.But it has plow acres and acres.split many cord of fire wood with a home made splitter .Driven many post with a home post driver .and is the only tractor , that I feel safe leaving running while I get on and off of .The parking lock holds it while I drive post .Split fire wood .I have it set up with ports for remote valves . I'like see if I can get to my service manual and try to post some pictures.Showing check vale location .


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## Always something (6 mo ago)




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## Always something (6 mo ago)




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## jd110 (Nov 23, 2015)

I agree with an earlier suggestion on the pto being the problem. I am assuming you have the independent pto with the lever between the gearshift levers? If hydraulics return when you disengage pto, then there is obviously excess leakage in the pto clutch circuit. There are internal lines that have a history of cracking. as well as seals on clutch drum and clutch piston that may have failed. By removing the transmission shift cover, it exposes 4-6 oil lines. There are orings that seal the lines to the cover, so be sure to replace those, but i doubt a blown oring would cause your issue. There will be either 2 or 4 smaller diameter lines. 2 if you only have independent pto. 4 if you also have the hydraulic HI-Lo shift on left side of steering column. blow compressed air in those small lines to see if any have excess leakage. To replace a broken oilne or reseal the pto clutch, tractor will need to be split.


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## Always something (6 mo ago)

b


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## Always something (6 mo ago)

Number 45 in my last post bottom picture is the stroke control valve intake screen .Most of my problem .Did the dealer service that ?
My tractor all manual .My service 
unal is for 2020 .The pump is the same .All my manual has for hydrlic high low is this diagram I am searching for pictures of the internal lines going to the high low .no luck yet


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## Always something (6 mo ago)

Ok One
More well 3 I don't think your tractor would have a shut off valve .My dose not.


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## Always something (6 mo ago)

Okay just one more .The only mention of a thermal relief vale is the test procedure. I can't find it in any diagram. Or picture.And I wonder if the elevated oil temperature is being caused by a blockage or malfunctioning oil cooler .


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## Always something (6 mo ago)

All of what you describe.Sounds like all of my issues looking at the high low pressure .It works on a lower pressure .If the Stroke Control is working properly it will squeak when it opens .If you are getting a constant squealing it could be stuck open .If stuck closed the pump will stop working .You will lose high hydrlic pressure.The main pickup screen in the transmission is designed to always have an open area for max fluid intake. The mesh of the stroke control screen is super tiny .Not micro but close .Small debress popcan find its way through the main pickup screen and find its way into the stroke control screen. if the screen gets clogged it will suck the screen seals into the stroke control and shut down normal function. You can pull the screen without pulling the pump. Remove the right side grill panel and the screen retainer cap is right there. WORK FAST HAVE A DRIP PAN BELOW THE CENTER OF THE DRAIN HOLE IN THE DUST PAN your going to lose fluid .Remove the cap pull the screen replace the cap quickly .I drain my hydrlic fluid when ever I service the hydrlic pump.
. 
This is the illustration of oil flow through the rock shaft system .when raised.When the high pressure leaves the pressure relief it flows through a oil galle to feed the rock shaft lift system .The remotes are fed by the pressure line that leaves the back side of the pressure relief .and into the bottom of the valve. Your loader pressure line should tee off that line .Fluid return comes out of the valve body directly into the rock shaft .Impossible to return spent loader fluid there .There is a port on the main filter housing and mine had male quick connection on it when I got it .I use that for my after market fluid return .Your loader return line might be hooked up there .Tell us what the final out come is .Where you you found the problem.


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## Tx Jim (Jul 28, 2020)

Always something said:


> All of what you describe.Sounds like all of my issues looking at the high low pressure .It works on a lower pressure .If the Stroke Control is working properly it will squeak when it opens .If you are getting a constant squealing it could be stuck open .If stuck closed the pump will stop working .You will lose high hydrlic pressure.


Not all stroke control valve make noises when operating correctly. Stroke control valve stuck OPEN = no hyd pressure, stroke control valve closed(seated) = hyd pressure. 

De-stroking screw was an factory OPTION which would depend on how dealer ordered each tractor.


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