When you say you checked the pump on the side, what work was done to it? Did you remove the pressure valve assembly and clean it? I've had two pumps that seemed good, but would not pump due to debris partially plugging the assembly.
How are you running your loader? If it is from the factory dual spool assembly it is going to be slow. That pump is not big enough to run a loader. Plus if you are running a loader from the factory valves you will not be able to run your 3pt due to the design of the hydraulic system.