Put the Redline 80W250 synthetic gear oil in the bevel box the other day and did my first long(ish) run today in 27c ambient temperature. Not any real change from running with the Redline Shockproof. Sad to say, it doesn't seem to be a miracle cure for noisy bevel boxes.
Another thing to consider, in reply to britmog, if you overfill a gearbox, it usually makes it run hotter because of the increased friction and drag of the extra oil. Extra heat is not what you want in the M3W Bevel Box.
