I have a four speed gearbox and the thing just keeps leaking gearbox oil. The leak is a slow leak, but it tends to be annoying when I park the car in friends driveways. The oil is leaking from the back of the gearbox where the drive shaft is going into the gearbox. The oil leak has even caused the oil level in the box to go really low, but at that point it stopped leaking. I changed the gearbox seal and refilled it with oil and now the leak has started again. Can anyone help me with this problem. Thanks.

You need a tailshaft bushing. You'll probably have to make one as I don't believe they are available.

A tailshaft bushing where does that go?

park the car with the motor point downwards to ease the leakage eheh. the bushing you need is possibly the one which goes around the inside of the gearbox where the tailshaft goes in. you'd need to undo the 4 nuts/bolts on the axle end of the tailshaft and take it off then investigate.

Did the tranny stop leaking for a short time before leaking again? If so then make sure your vent on the tranny isn't plugged off, or change the oil in the tranny to see if there is any metal in the oil, cause the metal particles can cause dammage to the seal.