Gehl 5640 Hydraulic issue.

[Oconnor1usa]

Parked my Gehl 5640 to change over the new fuel filter and top off the fluids.
Started up and runs like a top.
All hydraulics failed, bucket and motion. No noises or pump strain. Parking brake switch illuminates and safety restraint and seat switch allow for start.
Removed hydraulic filter and exit hose from the gear motor and no fluid flowed when engine was started.
Removed HALDEX 135930 ENGINEERED HYDRAULIC GEAR MOTOR and looks clean, and smooth in rotation.
Trouble shooting matrix points to
solenoids however, since all independent systems failed simultaneously, can anyone help?

 

[heymccall]

Is the pump coupling still intact? I have no idea how that one is built but, typically there will be a soft coupling between the flywheel and the first pump, inside the bellhousing.

 

[heymccall]

You have the pump off.. Does the mating shaft of the pump behind turn when the engine is started?
The gizmo in the middle here can fail...

 

[Oconnor1usa]

Thought that could be the problem, I have not taken the internal that mates to the engine out, I did start it and it did not rotate.
Was perplexed, hoping it was not going to be the inboard unit, 26114600b PUMP/TANDEM1 650453 CS 1/2 X 1-1/2 (L, P). I will pull it tomorrow, and take a look. That is the only thing I would expect to drive the pump. Thank you will keep you abreast.

 

[Mark13]

I'd say you've got some electrical issue with a sensor not registering to allow the hydraulics to work. I'd guess it probably has something to do with the lap bar not knowing it's down and that the machine can be operated vs sitting there idling with the lap bar up and no one in it.

 

[Oconnor1usa]

Normally, The engine will not start unless the lap bar is down, and that seams to be operational. The lap bar down and weight on the seat. I know they have a soft couple to fail and the unit is old. I was hoping it would be the switch, but when I took off the outer motor I expected the internal female spline to turn since the engine was running.

 

[lantraxco]

Normally, The engine will not start unless the lap bar is down, and that seams to be operational. The lap bar down and weight on the seat. I know they have a soft couple to fail and the unit is old. I was hoping it would be the switch, but when I took off the outer motor I expected the internal female spline to turn since the engine was running.

I'm not clear on what you're saying. Did you remove the gear PUMP from the end of the stack, and the drive coupler which is normally turning at engine speed was not turning? If so then for sure you have a coupler or other internal part broken, keeping the pumps from producing power.

 

[lantraxco]

Had that occur on a 500 hour customer machine, was an Owatonna Mustang. Managed to loosen things up and shift the whole pump stack forward with a comealong to the bucket enough to replace that drive plate. Customer story was very similar, parked it in it's spot at the end of a shift, started her the next morning and nothing would move. Things you remember from 40 years ago.

 

[digger242j]

Posting the same question in two different forums can create confusion, especially when both have replies to them. I've merged the two threads together into this one.

 

[Oconnor1usa]

Had that occur on a 500 hour customer machine, was an Owatonna Mustang. Managed to loosen things up and shift the whole pump stack forward with a comealong to the bucket enough to replace that drive plate. Customer story was very similar, parked it in it's spot at the end of a shift, started her the next morning and nothing would move. Things you remember from 40 years ago.

Sounds for great, will give it a try!

 

[Oconnor1usa]

Thank you for all the advise, I will give it a try.