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Dan
Dan, Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 4373
Experience:  17+ yrs. shop and field experience with all major brands of heavy equipment, trucks and farm equipment - 1995 WyoTech graduate.
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84 deere 410b turbo 4x4 super slow hydraulics 2900 lbs at

Customer Question

84 john deere 410b turbo 4x4 super slow hydraulics 2900 lbs at one test port on hydraulic pump and 0 pounds at the other test port on pump changed hydraulic filter, cleaned trans suction screen, cleaned screen in priority valve, something is stopping flow to the charge pump
Submitted: 11 months ago.
Category: Agriculture and Farm Equipment
Expert:  Dan replied 11 months ago.

Hi Tom, My name is***** see you changed the filter and cleaned the screen. If there was a lot of fine metal/debris in the filter and screen it indicates a pump or component failure. What is your serial number?

Customer: replied 11 months ago.
To410bg708978 no metal in screens just some silvery sludge from a leak additive that was added years ago
Expert:  Dan replied 11 months ago.

Hi Tom, Silvery sludge is actually a sign of failure. It will look like neversieze compound. There is no leak additive for hydraulic systems and if someone tried to put something in it will actually do the opposite and cause component wear and failure.

Customer: replied 11 months ago.
the pump has 2900 lbs nothing wrong with it i put the hydraulic leak stop in it years ago the charge pump on the front pump has flow (cracked the lines to it) yet the test port has no fluid coming from it if you have no experience with this machine please opt out this is the most sophisticated hydraulic system there is
Customer: replied 11 months ago.
not being mean just want to find someone that really knows this hydraulic system
Expert:  Dan replied 11 months ago.

Hi Tom. I worked for John Deere, Cat, Komatsu, and Volvo, and Excavators and cranes have the most sophisticated hydraulic systems. This is an older system. If the suction is not restricted or sucking air and the pump is not producing oil and the drive coupling between the engine and pump has not failed and is not slipping on the splines, you should have pump output and if not you have a pump problem. Check to see if you have an electric solenoid valve on your pump which disengages the pump for engine starting.

Expert:  Dan replied 11 months ago.

These pumps are known for some of the pistons to stick/fail as well. They are inside the hex plugs around the perimeter of the pump. If one or two fail the pump can still have output. Also you could have problems in the pump stroke control valve which strokes the pump for full flow. Since you say there is little to no output to the priority valve that would mean the problem is on the pump side.A failed pump can still have flow but not produce the proper GPM ( Gallons per minute) required by its specs nor produce enough flow to achieve relief pressure specs for the circuit.

Customer: replied 11 months ago.
i do its fine i have 2900 lbs at the test port it stays at 2900 i have fluid in the hose to the radiator cooler i have fluid at the hydraulic filter , i loosened the drain nut after changing the filter to bleed it out while running loosened it too much and took a bath in hy fluid the 2 test ports on the pump are for the main pressure and the charge pressure why isn't there any pressure on the charge ?
Expert:  Dan replied 11 months ago.

Charge pump pressure should be 85-105 PSI and 20 GPM New with a Minimum of 14 GPM used

Expert:  Dan replied 11 months ago.

Main standby Pressure 2755+- 50 PSI Flow at 2000 RPM 30 GPM New and 26.5 used

Expert:  Dan replied 11 months ago.

Priority valve setting 2100+-100PSI

System relief 3200-3400 PSI

Circuit reliefs are set individually and can post later if needed.

Customer: replied 11 months ago.
i now the problem is no pressure at the charge test port that tells me theres a problem on the return
Expert:  Dan replied 11 months ago.

There are two potential causes if there are no restrictions on the suction side. Either a problem in the destroke valve or you have a failed charge pump. The main pump is showing standby pressure and will as long as it is turning

Expert:  Dan replied 11 months ago.

Click this link for the parts breakdowns to help. Type in your model then go to sectional index. I have to run for my family obligations for new years but will be able to follow up further after the holiday.

Parts.

Customer: replied 11 months ago.
enjoy your day I go that page all the time what about the hydraulic return filter by-pass valve being stuck?
Expert:  Dan replied 11 months ago.

There would still be return flow through the filter. Try deadheading the charge pump side of the main pump assembly with a gauge on the end of the line and see what it will produce for charge pressure. If under spec. the charge pump section of the pump has failed

Expert:  Dan replied 11 months ago.

If there's no charge pressure there is no signal pressure to control the main pump.

Customer: replied 11 months ago.
the charge pump needs fluid to work i can remove the test plug while running no fluid from it at all
Customer: replied 11 months ago.
As far as pressure I must have plenty. I can lift the machine off the ground with each control. But it is super slow. Like I said. The only problem is no fluid out of the charge test plug. As far has gauging the line. I don't have anything here to that with.
Expert:  Dan replied 11 months ago.

The charge pump sucks in the oil on its own from the tank so if there are no leaks and its not siphoning oil through it and producing the specs I posted the charge pump is bad. With a bad charge pump the main pump may not reach full stroke to put out the GPM needed. You can have pressure with lower flow but it is the max flow that determines speed not pressure. Replace the charge pump section and inspect the stroke control valve for debris, bad o rings, damage, etc. Once you have charge pressure you can test the main pump for correct flow in full stroke to see if it is in specs.

Customer: replied 11 months ago.
Update. When I said I removed the lines from charge pump I meant line. The right right line. I just removed the left line which is from the transmission where the suction screen is. It has no fluid. While running. How does the fluid get pumped there? Does the charge pump pump it from from the transmission?
Expert:  Dan replied 11 months ago.

Yes that is correct and then it will run through the cooler, then out to the pump. check the transmission suction screen for a restriction or a restricted cooler. If the screen is clean, try bypassing the cooler direct to the pump for test purposes. There is also a valve on top of the cooler ( bypass valve).

Expert:  Dan replied 11 months ago.

Here is the diagram from the parts book

Expert:  Dan replied 11 months ago.

It scrambled a little but you can find it on the JD parts site. I have to head out now but keep me posted and Have a Safe and Happy New Years!!!

TRANSMISSION OIL COOLER TO HYDRAULIC PUMP AND TRANSMISSION OIL LINES
TRANSMISSION OIL COOLER TO HYDRAULIC PUMP AND TRANSMISSION OIL LINES-CONTINUED

CartKEYPART NO.PART NAMEQTYSERIAL NO.REMARKS

1AR21839CLAMP4

2........HOSE2185 MM LONG (3/4" X 7-1/2") (MAKE FROM T78497) (SUB FOR T61939, THIS APPLICATION)

3AR31547VALVE1

424H1685WASHER211/32" X 47/64" X 0.083"

519M7881SCREW2M8 X 20

6TY22464CLAMP2(SUB FOR AR21836)

7AT100980OIL COOLER1(WITHOUT AIR CONDITIONING) (SUB FOR AT69015)

T105890BRACKET2(BOLT TO BOTTOM OF RADIATOR TO HOLD ISOLATOR UP)

AT78602OIL COOLER1(WITH AIR CONDITIONING)

8AT69016HYDRAULIC HOSE1

CartKEYPART NO.PART NAMEQTYSERIAL NO.REMARKS

9H77698TIE BAND3(SUB FOR T44946)

10AT69017HYDRAULIC HOSE1

11AH75164ELBOW FITTING1

12R29936O-RING1

13T48176ADAPTER FITTING1

1419H2550CAP SCREW11/2" X 1-5/8"

15T21242WASHER2

16T28949CLAMP1

1719M7557CAP SCREW4M10 X 16, (WITH AIR CONDITIONING)

18R26448O-RING111.887 X 1.981 MM (0.468" X 5/64")

CartKEYPART NO.PART NAMEQTYSERIAL NO.REMARKS

19AT74103TEE FITTING1

Customer: replied 11 months ago.
Look at part 6. I removed that clamp and have pressure there. In above message. I removed the biggest line to the pump. Which comes from the transmission. No fluid running there
Expert:  Dan replied 11 months ago.

Run #10 direct to the pump for test purposes and see if you get charge pressure or if you have anything on that side of the cooler. My family is waiting... We will be able to follow up as needed. Happy New Year...

Customer: replied 11 months ago.
Well. Thought it was solved. Got excited. I removed hide no. 10. (Hose 8 has lots of fluid pressure). I started the machine and not a drop of fluid came out of 10. Assumed the cooler was clogged. I removed all the hosed and blew air each way. I got air to come out the other side. I put it back together and no difference. I removed hose 10 and again no fluid al all. Why air but no fluid?? So I hooked hose 8 out of the pump directly to hose 10. Tried the machine. No difference. Kept it running. Removed the charge test plug. Again no fluid. What the heck???
Customer: replied 11 months ago.
The valve prob doesn't open up unless the fluid is hot. But when I bubasse it all I still don't get fluid coming out of the test port
Customer: replied 11 months ago.
bypass
Expert:  Dan replied 11 months ago.

Thanks for the update Tom. Hope you had a great New years. I wanted to share some extra FYI on this issue. Click on this link.

FYI Troubleshooting.

Customer: replied 11 months ago.
I've read that link and every other one on the web. The fix was never mentioned. The writer stopped writing.
Customer: replied 11 months ago.
i think that will be my next step just take stuff apart and look at it
Expert:  Dan replied 11 months ago.

I would start by servicing the reverser and looking for metal in the filter and oil. If clean, check the pressures for the reverser to see if they are within spec for a potential problem there. Check the suction screen in the reverser that could be plugged restricting flow to the pump.

Customer: replied 11 months ago.
a suction screen in the reverser? You not mean the one in the transmission that I cleaned already right?
Expert:  Dan replied 11 months ago.

Thanks for the update. So the suction to the charge pump is clear. That is all I was trying to confirm. Id check the pressures in the reverser to confirm if they are in specs. I can post them for you if you need them.

Customer: replied 11 months ago.
I just removed the reverser filter. Clean as a whistle.
Expert:  Dan replied 11 months ago.

Looks like its time to start pulling bypass valve poppets and inspecting the valves for damage, wear, debris and clean/ reseal. I would also take a close look at the charge pump for internal wear and pump stroke control valves.

Customer: replied 11 months ago.
Does the fluid flow from the trans suction screen to the charge pump (on left) then out right? Or does it flow from the right out the left toward the suction screen?
Customer: replied 11 months ago.
I think the clue here is there is fluid pressure on the right side of the charge pump but no fluid on the left side
Customer: replied 11 months ago.
dan i dont want to guess anymore no disrespect I was hoping to find someone here that knows this system inside and out I have a manual, all the internet stuff, and I know everything that can cause this I just want to know exactly what it is this why i cam here in the past, i got the same thing, never solving the problem please find someone who knows this system and had this problem

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