3320 rockshaft quit again

About two months ago I reported that the rockshaft on my 3320 suddenly stopped working at 66 hours. I had lowered the 3ph with ballast box to the ground, shut down for a few minutes and then on restart the 3ph would not lift. No response at all. After a few min of fiddling/shutting on/off the rockshaft suddenly worked again.

A few days later I changed the hydraulic fluid/filter and found several bits of metal shavings.

Today at 71 hours I had a repeat of the failure, absolutely no response to the rockshaft control about 10 min into a project. I think that the rockshaft hydraulic bypass valve was stuck in an open position. As I had the rockshaft drop rate control set for a somewhat slow drop, I tried opening for a faster drop, restarted and the 3ph lift suddenly worked again. Now I recall that fiddling with the drop rate control valve cleared the problem the 1st time.

I don’t know how the drop rate control valve relates to the rockshaft hydraulic bypass valve, maybe someone here can fill me in.

Woody

On some tractors when the rate of drop valve is closed, it also restricts raising. I am not sure whether or not this is the case for your tractor. My working theory is that perhaps since you had it set for a slow drop that perhaps you hit the knob with your foot while getting on or off and moved it enought to totally close it.

You could test this theory by first seeing if closing the rate of drop does prevent raising, the see how much movement of the valve knob is required to go from the slow drop to totally closed.

RogerH said:

On some tractors when the rate of drop valve is closed, it also restricts raising. I am not sure whether or not this is the case for your tractor. My working theory is that perhaps since you had it set for a slow drop that perhaps you hit the knob with your foot while getting on or off and moved it enought to totally close it.

You could test this theory by first seeing if closing the rate of drop does prevent raising, the see how much movement of the valve knob is required to go from the slow drop to totally closed.

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It takes several complete turns of the knob to close the drop valve. Once closed, the 3ph is locked. Attempted lifting results in an almost engine stall. That was not the case that I had, there was no response at all to moving the leaver.

In normal operation, regulation of drop speed does not alter the lift speed.

Struck out on my first idea.

Do you have a diverter valve kit on your tractor? I saw what you describe several years ago on a tractor with a diverter valve. Upon starting the 3 pt wouldn't lift until the joystick was jostled. It seems the diverter was stuck between two positions, thus blocking the flow.