Have you ever shot it Voo to find out for sure :2guns:
The usual culprit for the layshaft gear (your 14T) stripping is the engine mounts coming loose. This causes the engine to move under hard acceleration and parts the mesh with the diff ring gear. Check the engine mounts are tight as part of your clean down & maintenance after every run, this is key to reliability. If you spend an hour cleaning & making sure everything is tight after each run you should have a reasonably reliable car even in std plastic form.
Sounds like you are on top of yours but you get some people whinging about how their car breaks on every outing but they don't bother giving it a little bit of TLC after each bash and eventually everything works loose and causes breakages, bash sessions to end early and frustration with the car.
Ive just converted 1 of mine to 4wd and its awesome, Im well impressed with it :cool2: How are you liking yours?