Hi Michelle, what make & model is your car? A hole in the gearbox casing is caused either by something on the inside breaking and being smashed through the casing by the gearbox internals or by being struck by something that you have driven over or has been thrown-up from the road and struck the transmission casing. Either way, replacing the gearbox with a good used / reconditioned unit is probably the quickest and cheapest option, fitting a new clutch when the gearbox is changed would probably be a good idea too, as the work required to change the clutch is exactly the same as replacing the gearbox.
Magik Joe, April 2014
