Ever since I swapped in my sm420 - previous owner said was in good condition - hence no new bearing kit installed - I have either a gear mesh noise or bearing noise that increases with speed, not rpm's. I called Rube - since I used his adapter and he said it was possible that the bull gear had a different pitch to it than his adapter was machined for. He thought it would go away with time. Well...it hasn't. I drove it from SoCal to the Con and back - and the noise gets louder as the tranny warms up - i.e. tranny oil thins out more. Is this a bearing - or something else? Any input appreciated. TIA.