Did you verify that the driveshaft connection to from the engine to pump is solid? Sometimes the pins on driveshaft break or fall out. The engine may be running but the pump ain't turning. Very common problem.

Another common remedy to no hydro problem is a simple oil and filter change. Make sure you have the right filter. A hydro should never be run without oil.

Finally, the tractor will not move one way or the other if one or both of the relief valves buttons are depressed. One relief valve is for forward and the other is reverse.

Thanks. I pulled the differential cover and it was more or less full. There was heavy sludge buildup.


As for those valves, if I use the toggle switch in the center console one of them will stick. Do they need to pop open and closed during operation or as long as I dont use the toggle switch and keep them open, then it should operate?

I will try to double check the other things you mention. I see the fan portion in the center is spinning, are those rods a bit further back closer to the pump?

The tits on the release valves are up under normal operation. They have springs inside that pops them back up after you push them down. If they are not stuck down firmly, the pressure that the running hydro builds will pop them back.

If you try to push the tractor the hydro should not be running, the release lever pushes the pins down and releases the hydro. You will not be able to release the rear wheels while both wheels are on the ground if the pins are up.....period. When the rear wheels are jacked up and not running, and you try to move them by hand, one or the other will rotate in either direction one at a time, but both will not turn in the same direction at the same time, regardless of whether the release pins are up or down..

The hydro gets filled through the plug hole until it is full to the hole. Just because you can't look in and see any fluid doesn't mean it is too low to operate. Try to determine just how low it really is.

Thanks for confirming the buttons stay up when the tractor is moving. So I can use the tractor even if one sticks, I would just have to manually release it if i had closed them to push it.

I confirmed the pin holding the drive shaft to the pump are intact. I drained and cleaned the differential, it was black with cottage cheese like gel... now i just wait for the rtv to dry and will give it another a try in the morning.

I had success this morning in getting it to engage with just an oil change and new filter.

I just want to confirm about the relief valves:

As long as I keep both in the out position, the tractor will move with engine running, correct?

If either gets depressed they will stick and I am unclear if they have to open and close while in operation.

That is correct.

They (both) will always be out and will not go in on their own. You must push them in manually when you want to push/move the tractor manually without the motor running.
Once released, properly operating valves will pop back out on their own whether the motor is running or not, however slightly stuck valves may pop out once you start the motor.
If they are in, whether stuck or being manually held in when the motor is running the tractor will not mover on it's own.