2007 3520 Power Reverser won't move

[tuolumne]

Four things could prevent a reading from the Lubrication port:
1 Orifice N is plugged
2 Lubrication relief valve O is stuck open
3 Lubrication shutoff valve M not opening (stuck closed)?
4 Modulation valve P not opening



3

I have completely reassembled. The components for items 1-4 above appear very simple with no damage.

Current symptoms are as follows: no forward/reverse, and also no PTO. The PTO may have been not working originally - I did not test it before the first tear-down. This may be a clue.

Forward test port results per spec.
Reverse test port results per spec.

Lubrication test port reads about 35 psi with the clutch in and 0 with it out while the machine is in neutral. When the clutch is pushed in it jumps to 35 right away, but when let out is slowly drifts to zero. With the clutch out and the machine placed in forward or reverse, the pressure goes quickly up to 35 psi, then drifts back down to 5.

Does this data provide some helpful direction?

 

[radios1]

The machine has new hyrdraulic oil, new suction filter, new inline filters.

with all you have done, and checked, the oil should be going into the clutches, and engaging them. very odd.. maybe something like a gear or shaft broke..

 

[tuolumne]

with all you have done, and checked, the oil should be going into the clutches, and engaging them. very odd.. maybe something like a gear or shaft broke..

I hope the PTO is a clue. Oil to the PTO clutch passes through the reverser valve. Because of this, I do not suspect that the issue is with the drive clutch or something mechanical beyond it. Also, there is the low pressure reading at the lubrication test port.

 

[tuolumne]

More speculation.....I do not see the pressure relief valve in the theory of operation diagram. Is is possible that this is letting the oil flow through and not allow pressure to reach the PTO solenoid or the clutch? Could the spring (item ap in the diagram on page 1) lose its pressure? There are no other parts in that valve that could have a problem.

What pressure is the relief valve set for? Is it the 270 psi that I read at the other ports? If so, where is pressure reduced? At the pump? What would wear such a spring out? During normal operation is the pressure relief always dumping extra, or only if there is a problem? This machine has lots of high RPM hours where it is stationary with no PTO action either, such as using the backhoe, my sawmill, or a log forwarder.

 

[beenthere]

tuolumne
Is Mtn View Imp where you can take it? or is there a better place closer?

 

[tuolumne]

tuolumne
Is Mtn View Imp where you can take it? or is there a better place closer?

Right now the operator station, tires etc. are removed so it can't be taken anywhere. Mtn View equip has field techs that can come out from 90 minutes drive time away. That gets expensive quickly; especially because I have been on the phone with them and they are not familiar with this machine or its specific problem. I'll keep wrestling for now!

 

[Zebrafive]

I have completely reassembled. The components for items 1-4 above appear very simple with no damage.

Current symptoms are as follows: no forward/reverse, and also no PTO. The PTO may have been not working originally - I did not test it before the first tear-down. This may be a clue.

Forward test port results per spec.
Reverse test port results per spec.

Lubrication test port reads about 35 psi with the clutch in and 0 with it out while the machine is in neutral. When the clutch is pushed in it jumps to 35 right away, but when let out is slowly drifts to zero. With the clutch out and the machine placed in forward or reverse, the pressure goes quickly up to 35 psi, then drifts back down to 5.

Does this data provide some helpful direction?

There is tube from the Reverser valve to the PTO solenoid valve. From the PTO solenoid valve a tube goes to the PTO clutch. Maybe connector(s)/wiring/switch/solenoid problem for no PTO?. Or no hydraulic pressure?, but since you have pressure for F/R clutches, I doubt pressure is the problem. More likely solenoid or switch/wiring/connector(s). I assume there is a PTO pressure test port, maybe in the PTO valve? Final thing could be failed PTO clutch pack

 

[Zebrafive]

More speculation.....I do not see the pressure relief valve in the theory of operation diagram. Is is possible that this is letting the oil flow through and not allow pressure to reach the PTO solenoid or the clutch? Could the spring (item ap in the diagram on page 1) lose its pressure? There are no other parts in that valve that could have a problem.

What pressure is the relief valve set for? Is it the 270 psi that I read at the other ports? If so, where is pressure reduced? At the pump? What would wear such a spring out? During normal operation is the pressure relief always dumping extra, or only if there is a problem? This machine has lots of high RPM hours where it is stationary with no PTO action either, such as using the backhoe, my sawmill, or a log forwarder.

Sorry, I am not sure how the system pressure for Reverser is controlled. Your tech manual should tell.

Parts drawing from JD parts does not identify the relief valve. Maybe your tech manual does?

 

[Zebrafive]

I hope the PTO is a clue. Oil to the PTO clutch passes through the reverser valve. Because of this, I do not suspect that the issue is with the drive clutch or something mechanical beyond it. Also, there is the low pressure reading at the lubrication test port.

Does tech manual tell what lube pressure should be? If low, maybe lube relief valve stuck or weak spring?

 

[Zebrafive]

with all you have done, and checked, the oil should be going into the clutches, and engaging them. very odd.. maybe something like a gear or shaft broke..

Or torsional damper has failed?