Re: My \"NEW\" Tractor
As long as you do not operate the rear hydraulics, the fluid is diverted back into the tractor and it is safe have the stop valve closed.
If you operate the three point hydraulic valve with the stop valve closed, then the fluid have no where to go. This is bad for your pump.
The exception...
There is usally a hydraulic port on the 3 point hydraulic valve. So you can connect and additional hydraulic implement instead of your three point lift cylinder that is operated from your three point valve. Once you make the connection, then by closing the stop valve, you divert the fluid to your additional implement.