Hi Cam, you have the opposite of the normal problem, usually the 3PT will not go down.
First is your draft control lever all the way forward.
I suspect there is a problem with the 3PT lever linkage since you say PS, PB, PTO and Remotes work properly, there is an inspection cover that can be removed under the seat.
Your 385 is like a 454 but with the smaller D-155 engine, see link below for manuals for 454, the service manual has a complete section on testing and trouble shooting hydraulic system.
These manuals are for the Euro version tractors so there are slight differences especially with the electrics and there have been some improvements from 54/74/84 to 85 series.
See also these links: