I'm out of country, but my son has been keeping my SIII running. He now tells me that, in the course of parking it at a store, he experienced a sort of "bang" when maneuvering. After that, he had no forward gears (just some whirring), but he still had reverse. So he got the Rover home by reversing it the mile or so back, where it now sits. My initial thought was the transfer had slipped into neutral, but that doesn't explain the existence of reverse only. What am I likely facing when I get back?