Julesb,
From your description I think prob lies wit clutch cable/dump valve adjustment which has the result of causing a conflict between clutch potentiometer and pressure switches and pwm solenoid and tcm thus no drive, tractor moves couple of feet drive lost or cp on dash. To adjust cable remove return spring on dump valve lever( on trans side cover inside accumulator) then loosen lock nuts on clutch cable and with 31.5mm spacer against bulkhead depress clutch pedal to touch spacer. Then pull outer casing of cable down until inner cable is taut, with cable still held taut thread lower nut up against bracket to hold tension. Lock cable in this position using upper nut. Reattach return spring to lever and all is hopefully ok!!!!! Other possible causes are dump valve retaining bracket cracked on inside of trans control valve similar symptoms to cable adjustment ( seen on tractor last week after trans had 23000hrs on clock) or problem with 5volt line reference from tcm(pwm solenoid amps incorrect voltage ok) v common on tractors with electro link
Kevc
