Try the specialist forums. Tractors are a bit niche.
https://www.tractorforum.com/threads/jcb-3cx-movement-problems.17257/
https://thefarmingforum.co.uk/index.php?threads/jcb-gears-missing.90984/
https://www.plantandconstruction.co.uk/forum/plant-repairs-maintenance-mods-workshop-discussion/damn-its-broken-again/1689-
2iejh, October 2021