Hi I've had my 59 plate xf luxury premium for just over 2 years and love it but I've had a gear box error come up a few times once on the motorway stopped to pay roll on bridge pulled off went though gears to 4th then fault came up pulled over stopped engine restarted all fine second time going up hill used paddle to change up and error cane up same thing stopped engine and then all good its like if you slip to neutral revs go up but no drive any ideas please