Laurens, maybe try contacting Terence Goad at Garage 56. They had a bevel box in pieces a few months ago with a view to coming up with a marketable solution to the problem of noisy bevel gearboxes. I haven't heard anything from him and I asked him to let me know if they fixed it. "Bwitched" did a detailed write up about his bevel box rebuild in April 2015 on TM and managed a quite BB with correct tolerances.
