M5700HD Shuttle Issues

[JPCoyne]

Good day. Seems like we have more issues then originally thought on our tractor. M5700HD with a lil over 2000 hours on it. Once this unit was getting warmed up, we were losing the ability to move forward. Also, even when cold, you could push the brakes and lets call it disengage the forward clutch pack ( would kick the hyd pressure out and you would have to move the shift lever from F to N then back to F). We checked all the basics, fuild level, linkage all with spec for the shuttle valve, filters changed and system primed. Preformed the shuttle valve system pressure test and found that we weren't getting proper pressure on the forward port. Disassembled the valve and found a broken spring and worn components. Contacted Kubota whom stated because of the year of this tractor they dont offer any components and we had to purchase a new valve. Pulled the trigger and install the new shuttle valve. Now we have proper pressure that matches the range in the WSM. Something is still wrong. When cold, takes about 2 seconds once FNR lever in F and clutch pedal is lifed to start to move forward and then the Modulation port pressure gets into proper range, R is a like faster maybe 1.5 Secs but pressure is the same as the F. Once tractor gets warmed up time frame increase by 2 seconds or so ( 4 seconds to start to move forward, Reverse is around 3 seconds). Kicker added to it, if you are turning the wheel while in forward or reverse and lift the pedal to go to drive you will get nothing on the Modulation test port. Let go of the wheel and in about 2 to 3 seconds pressure will build in the test port and you will start to move.

260psi at 2600 rpms with the pedal fully pressed and free in both forward and reverse on the M port. Forward and Reverse test ports are at 265ish psi when fully engaged. But if hot and turn the wheel hard, nothing. I fell as if its a upstream issue, Hyd Pump or possible the oil cooler relief valve. Was wondering yalls thoughts.

https://drive.google.com/file/d/1ZlyX8nqBCrZci9NTZbGvZwmoT-sCrMc_/view?usp=drive_link

 

[PoTreeBoy]

Good day. Seems like we have more issues then originally thought on our tractor. M5700HD with a lil over 2000 hours on it. Once this unit was getting warmed up, we were losing the ability to move forward. Also, even when cold, you could push the brakes and lets call it disengage the forward clutch pack ( would kick the hyd pressure out and you would have to move the shift lever from F to N then back to F). We checked all the basics, fuild level, linkage all with spec for the shuttle valve, filters changed and system primed. Preformed the shuttle valve system pressure test and found that we weren't getting proper pressure on the forward port. Disassembled the valve and found a broken spring and worn components. Contacted Kubota whom stated because of the year of this tractor they dont offer any components and we had to purchase a new valve. Pulled the trigger and install the new shuttle valve. Now we have proper pressure that matches the range in the WSM. Something is still wrong. When cold, takes about 2 seconds once FNR lever in F and clutch pedal is lifed to start to move forward and then the Modulation port pressure gets into proper range, R is a like faster maybe 1.5 Secs but pressure is the same as the F. Once tractor gets warmed up time frame increase by 2 seconds or so ( 4 seconds to start to move forward, Reverse is around 3 seconds). Kicker added to it, if you are turning the wheel while in forward or reverse and lift the pedal to go to drive you will get nothing on the Modulation test port. Let go of the wheel and in about 2 to 3 seconds pressure will build in the test port and you will start to move.

260psi at 2600 rpms with the pedal fully pressed and free in both forward and reverse on the M port. Forward and Reverse test ports are at 265ish psi when fully engaged. But if hot and turn the wheel hard, nothing. I fell as if its a upstream issue, Hyd Pump or possible the oil cooler relief valve. Was wondering yalls thoughts.

https://drive.google.com/file/d/1ZlyX8nqBCrZci9NTZbGvZwmoT-sCrMc_/view?usp=drive_link

First, it sounds like you have a WorkShop Manual, but, if you don't, you can download it at KubotaBooks. The HD model gets its own sections in an addendum near the end.

You say you recently changed both hydraulic filters, correct? Tell us a little about these symptoms - did it start recently or has it behaved this way since you've owned it?

Here's the steering/shuttle diagram

I may have missed it, but I don't recall a troubleshooting guide in the clutch/transmission sections. So, I'd start by checking the modulating pressure at the A test port. With the transmission in N and the clutch engaged, it looks like the pressure should be 600+ psi. Fully disengaged, it should be minimal.

Much less than 600 would indicate a problem upstream, cooler, cooler relief, steering box possibly. Let us know what you measure.

EDIT, I missed that the shuttle shift bleeds off the modulator in neutral, so you won't see 600psi. Here's the test pressures, M port in the chart corresponds to the A port on the hydraulic diagram.

 

[JPCoyne]

Thank you for the response. I have the WSM for the tractor but the section for the shuttle valve sections could be better. Last season the tractor started showing some issues once it was running for a while. Lose of motion, but seemed to have better reverse than forward if that makes sense. Reverse still engaged fully and you could push down on the brakes and bog down the engine. However while going forward you could push the brake and would "disconnect" the hyds but never bog down the engine. But you could push the clutch in and release and it would start to move forward again. Put it off and serviced the unit hoping it would resolve this issue. It did not lol. Which lead me down to buy the WSM and preform the shuttle vavle pressure test. Test failed on the F port, disassembled the valve, found damaged components, replaced with new valve, now hyds lock in forward and bog down engine same as reverse. But still have a funky pressure issue at engagement once hot.

As far as test procedure.....

F port - fully pressed 0 psi
- free 265 psi
R port - fully pressed 0 psi
- free 265 psi
M port - 360 psi Forward and Reverse

"seem to build pressure slower then they should"

M port in neutral is 0 psi or at least not showing up on my gauge 0-1000psi

The kicker is when turning the steering wheel hard, once hot, and taking off in gear with the pedal released. No pressure will show on the M port until you let go of the steering wheel and let it find a natural state. Pressure slowly will build and you can feel the clutch packs engage.

 

[North Idaho Wolfman]

Have you checked this pressure relief valve?

 

[North Idaho Wolfman]

The other possibility is that you have bad seals in the clutch packs.

 

[PoTreeBoy]

Thank you for the response. I have the WSM for the tractor but the section for the shuttle valve sections could be better. Last season the tractor started showing some issues once it was running for a while. Lose of motion, but seemed to have better reverse than forward if that makes sense. Reverse still engaged fully and you could push down on the brakes and bog down the engine. However while going forward you could push the brake and would "disconnect" the hyds but never bog down the engine. But you could push the clutch in and release and it would start to move forward again. Put it off and serviced the unit hoping it would resolve this issue. It did not lol. Which lead me down to buy the WSM and preform the shuttle vavle pressure test. Test failed on the F port, disassembled the valve, found damaged components, replaced with new valve, now hyds lock in forward and bog down engine same as reverse. But still have a funky pressure issue at engagement once hot.

As far as test procedure.....

F port - fully pressed 0 psi
- free 265 psi
R port - fully pressed 0 psi
- free 265 psi
M port - 360 psi Forward and Reverse

"seem to build pressure slower then they should"

M port in neutral is 0 psi or at least not showing up on my gauge 0-1000psi

The kicker is when turning the steering wheel hard, once hot, and taking off in gear with the pedal released. No pressure will show on the M port until you let go of the steering wheel and let it find a natural state. Pressure slowly will build and you can feel the clutch packs engage.

Well, the pressures check out, indicating the cooler relief and PTO clutch relief valves are working correctly. I've tried to come up with a scenario that the steering controller could be at fault, but I don't think so.

It seems that you just don't have enough flow to supply the clutch. This could be caused by
1 Weak/worn pump - apparently you have sufficient flow for the steering to work correctly, so this is low probability. But considering the PITA to correct 2, it might be worth testing the pump first.
2 Internal leakage between the shuttle valve and the clutches, including the clutch packs themselves. As @North Idaho Wolfman said, there are seal rings to seal the passages to the clutches. If the internal leakage is too much, there won't be enough pressure left to apply the clutches.

I'll ask, the specified fluid is SUDT. What are you using?

 

[whitetiger]

The bad news is that when the forward pack was operating with low pressure, the clutch pack was slipping and has toasted some of the clutch discs. There is only one way to repair the slipage at this point.

The tractor will need to be separated and the clutch packs rebuilt.

I just went through this same scenario with an M135 from a large ranch in Arkansas. He had it hauled 7 hours up here after visiting several of his local dealers.

 

[JPCoyne]

Thank yall for the responses. We are running kubotas SUDT only. The steering isn't what you would say correct 100%. Failed to mention that on the original post. At low ideal once hot does seem to take more effort to turn those tires at a dead stop. And that's when you can turn the wheel and get no flow into the M port of the shuttle valve. Once releasing the steerting wheel pressure slowly returns and tractor will start to move. Going to pull that relief valve off first give it a good visual inspection. If we don't see anything crazy probably will go get the hydraulic pump tested and inspected. Trying to do everything externally first. Please let me know y'all's thoughts.

 

[Fedup]

You have a lot of qualified help here, and not going against anything mentioned so far, my next suspect would be the steering pump. Shuttle and PTO valves are downstream of the steering valve. Steering relief valve is no doubt built into the steering valve, so whatever goes over relief still goes downstream to those other circuits. As you are explaining this my impression is when the steering is loaded to it's relief point nothing is going downstream. As such, PTO probably stops as well as the shuttle clutch pack. That would indicate the pump isn't supplying enough flow (and/or pressure) to open the steering relief.

Questionable condition of shuttle clutch packs not withstanding, I see the lack of proper steering as the point to address first. Once that's resolved see what remains of the other issues.

 

[PoTreeBoy]

Thank yall for the responses. We are running kubotas SUDT only. The steering isn't what you would say correct 100%. Failed to mention that on the original post. At low ideal once hot does seem to take more effort to turn those tires at a dead stop. And that's when you can turn the wheel and get no flow into the M port of the shuttle valve. Once releasing the steerting wheel pressure slowly returns and tractor will start to move. Going to pull that relief valve off first give it a good visual inspection. If we don't see anything crazy probably will go get the hydraulic pump tested and inspected. Trying to do everything externally first. Please let me know y'all's thoughts.

Sounds like a good plan. I doubt it's check valves, but they're easy to look at. If you're close to a dealer and they have the test kit, they should be able to test the pump without removing it, according to the WSM. Hopefully you won't have to go into the transmission.