does your 445 have the optional shut off installed in the circuit. I think these are usually in the front right corner of the tractor but not 100% sure of that.
Double check the linkage to the directional valve. make sure that both spools are moving an equal amount. Junk could have accumulated around the linkage over the years preventing one of the spool from moving completely.
Typically valves are not rebuildable with exception of a couple of shaft seals that prevent tank line oil from seeping out onto the ground.
![100_0531[1].jpg](https://www.tractorbynet.com/forums/data/attachments/501/501391-0e90ac582b1235082de5eeb2468f5d51.jpg "100_0531[1].jpg")
I have been upgrading from a JD 316 (Dual spool added) to a JD 445 for the spray tractor. The 445 was used by a city as a plow tractor when I got it. When I got it I was only interested in a mow tractor. As a mow tractor the deck went up and down as it should. Now I am making the 445 my spray tractor. I have hydraulics on the wings of my sprayer. They worked fine on the 316. But when I connect them to the 445 it doesn't function. I am trying to figure out if I should rebuild the existing Controller or just get another one.