Need some input on a left side final drive that won't move. Final drive was replaced and problem not resolved. Capped off forward and reverse lines and operated left side. No change in engine rpms. Replaced hydrostatic pump, fluid and filter were changed. Left side worked for 15 minutes and stopped. Removed pump and final drive for testing. Was told no problem with either just cleaned material out. Reinstall both, left side worked for 15 minutes and stopped. Capped off lines and operated left. Engine runs dropped. Tee's in pressure gage to park brake line and had 400psi to brake and drive was working. Ran left side for 40 minutes with no problem. Removed tee and Reinstall line, no left side drive. Reinstall tee and I have 400psi to brake with no drive. I'm ready to jump on the Harley and leave town. Wtf is going on here!