I have just finished replacing the charge pump and one of the pick up lines on my 2440. The Hi-Lo works, the power steering works again, the three point hitch works, the only thing i cant get to work is the PTO. When i pull up on the lever it makes a whining/groaning sound but it wont engage. The tractor also makes a groaning sound at lower RPMS but clears up when given throttle (1800 RPM and higher). The groaning sounds somewhat like a power steering pump with bad bearings. Could someone give me somewhere to start with diagnosing this? Thanks!