I have a 1974 Case 580B backhoe with power shuttle. Recently it would intermittently stop moving or lose power when driving. Now it will not move at all in forward or reverse. The fluid level for the transmission and power shuttle are both good. I am suspecting that the screen on the shuttle pump suction is plugged as I discovered that the cap off the breather was missing. Looking for some guidance as to the best way to clean the screen.
Is the trans pump making a lot of noise? Check filter in front of radiator, also check the declutch pedal and make sure it's coming all the way back up.
There is a Mega amount of information recorded on this site re 580B shuttle transmissions. You can drill through the bottom of the transmission housing to gain direct access to the screen - just read this thread
I am NOT a fan of drilling the housing go ahead and pull the upper housing cover and do it right.
The transmission pump doesn’t make too much noise. The declutch pedal is fully up and since this problem started it is very hard to push down. I have to stomp on the pedal to get it to go down. I checked the filter by the front of the rad and it didn’t look plugged. I am planning to replace it anyway.
Sounds like you might have a problem in your control valve for shuttle sense you're having an issue with declutch pedal.
Any idea what the problem might be with the control valve? Planning to attempt to remove the control valve later this summer, it looks quite an intimidating job. Is there anything that I should be more careful with when removing the valve? With the valve off the machine is it possible to access the suction tube for the pump?
When you remove the valve be careful the detent spring that rides on shift spool will pop out. Tap the valve with a hammer to break it loose and as you raise it up watch spring and be mindful of where it goes. If you need to get to pump and suction you will have to remove large plate that valve sits on. You will have to remove bolts that hold steering column and lift it up with com-a-long.
I was trying to move the backhoe off the road with the bucket and the couldn’t get it to move. Lifted the back tires off the ground with the stabs and one tire turns freely by hand and the other will not turn.
You might have a locked up brake on that side that won't move, check that first.
Got the brake frees up but still won’t move. Trying to rank the cover off the pump and suction line now. Is there any secrets to getting the fuel tank out? We have the nuts removed from all of the mounts but it does not lift up high enough to clear the studs?
I never took the fuel tank off, just take bolts that hold the steering column out and lift the column up with a come-a-long attached to the canopy. Then remove the valve and then the top plate block it with a 2x4 and remove the suction tube and pump.
Removed the pump and suction tube and both look good. The screen at the bottom of the tube was completely clean. Is there anything that could be wrong with the valve assembly regulator that would cause the declutch pedal to be overly stiff and prevent the backhoe from moving?
The declutch spool in the valve, where the clutch pedal connects to valve could be an issue. Are you sure you don't have another issue with four speed transaxle and or differential?
The reason I think there might something wrong with the valve or spool is the declutch pedal is normal and can be pressed easily when the engine is not running. As soon as you start the engine the pedal becomes so stiff that you can not press it down.
Check the gasket for being blown or a crack in valve body
I removed the pump and suction tube and cleaned and inspected both and they appear to be good. The suction tube was not plugged up at all, so that is definitely not the issue. I replaced all of the gaskets when I reassembled and checked all of the plates/valve body for cracks and none were found. After reassembly, the declutch pedal is still very hard to press when the machine is running. When the machine is warmed up and put in gear I push the throttle down and the tires will turn very slowly, when I release the throttle pedal the tires accelerate very quickly for a couple of seconds and then slowly stop again.
If you put shuttle in neutral does machine try to move?
The machine does not try to move when in neutral. With the rear tires lifted off the ground if i put the shuttle in gear and put it in forward, the tires will spin slowly backwards until I give it some throttle and then they slowly stop and go forward very slowly with no power. I can hold the wheels from turning with my hand. If I put the shuttle in reverse the wheels will turn slowly even when I push the throttle. When I release the throttle the wheels will speed up for a few seconds and then slow back down again.
Have you checked shuttle pressure at regulator valve? Have you tried turning the eccentric bolt to adjust the declutch pedal travel? It still sounds like something in the control valve to cause the pedal not to want to move when machine is running.
Do you know what the fitting size is at the regulator valve? I would like to pick up a gauge this week so I can test it this weekend. What pressure should I see? Are there any components in/on the control valve that can fail and cause the pedal to not want to move?
It should be 1/8" NPT