My 1999 Discovery 2 Td5 has an oil leak on the automatic gearbox; it appears to be in the centre of the gearbox where it joins together. The box is losing about a litre every 10,000 miles. What do you think is wrong?
From your description, it seems the oil is leaking from the joint of the torque converter housing (visually similar to a manual gearbox’s bellhousing) and the gearbox proper.
The bolts holding the torque converter housing to the gearbox are inside the torque converter housing: to access them the auto transmission must be removed. That done, the torque converter can be withdrawn from its housing, giving access to the bolts.
Just tightening the bolts won’t guarantee a fix. The torque converter housing should be detached from the gearbox and the oil seal and the intermediate plate gasket renewed. The seal and gasket cost about £20, but we understand the job takes about six hours, which could mean a garage bill of £350 or so.