Mine has recessed letters, so was considering the sharpie idea. Too busy at work and no time to play. Have you done any oiling to your air system on the M923? It is an old trick on the M54 to add a touch of oil to the airline to lube the airpack. Was wondering about a touch of machine oil to lube the six wheel drive portion. When I first got it, was not getting air at the switch, now that seems to be working.