My Dads x5 lost all drive he took it to a BMW specialists we use and he found a fault with a tooth in the rear diff somewhere (im not sure of the exact details)! Fixed it and all was good, now the abs lights, traction control light and a 'mechanical fault with trans' message on the dash ans is in 2 wheel drive. The same guy reset the codes but theyve come back again, and the guy recons he needs a new or recon transfer box!. I'd like to get a second opinion on this as I dont see how there could suddenly be a fault with it when the wasnt before.. Soooo anyone know any good bmw specialists or 4x4 transmission specialists in or around teh west midlands? Cheers.