Thanks for all the info. This is where I show my ignorance of gearboxes, the box is in bits at the moment, apparently so that the teeth could be inspected, but I don't know what normal syncros look like. It doesn't have a bellhousing, and I haven't been able to speak to the bloke that I got it off to find out off him what he knows. Can anyone show me the difference between the two types of syncros?