So, I have a 4.4tdv8 with the rotary gear selector and a few months ago it packed up and would lock in gear - I’ve had it rebuilt twice but it’s gone again. Intermittently locking, luckily in car parks not at traffic lights!

Do I bite the bullet and get a brand new unit or try again with this one - another rebuild would be covered by warranty. Can I fit it myself (which I can do) or would a new unit need to be coded to the car?