how do calibrate clutch on ford 6640 dual power?

With gears in neutral start tractor while holding both buttons in on gear shift.
Cal should show on gear panel
have revs at 1200
Clutch in and put both gear selectors in forward
Hold in top black button numbers in gear gauge should go to close to 200
Then do bottom black button the same.
you will feel a clunk in gear box
put gears back to neutral then using clutch place in gear and it should show on selector gauge.
I have found to prevent the PTO not working properly after this to have PTO under load and working whilst sychronizing

Andrew
October 2014