ST5000 Autopilot problem(s)

[Mijoy2]

This unit behaves strangely.

The pump appears to be okay, I can bypass the unit and it works well.

If I am in standby, then press auto, the unit will appear to want to move the pump motor but almost instantly force itself back to auto.

Also, if I press +-10 degrees from standby nothing happens at all.
If I press +-1 degree from standby the pump makes strange noises (seems to want to work but will not) almost as though there is too little fluid in the hydraulics.

any thoughts?