Adding a wet kit

I’ve got my wet kit all on and tried it on a frame type dump trailer and when I engage the pto, with clutch depressed, then pull the knob to raise, I get nothing. I’ve got my air lines run just like the diagram that was posted. When I move the pto switch with truck not running, I’m not hearing the fork slide the gear but the gear does slightly grind when truck is running and I flip the switch without depressing the clutch. Everything seemed to work fine before I put the pump on the gearbox.