Hyundai Repair: tiburon 2003 V6 Gt axle leak, gearbox oil, axle shaft

Question
recently did a clutch/flywheel change (thank you for the tip by the way) it went smooth.
since that i do have some small leak of oil at the level of the seal when the axle shaft go into the gearbox. the seal were good and shaft as well, the question is  :
is overservicing the gearbox would generate oil to leak when the gearbox is static after running the car? (Oil more fluid, level above the seal ring...)
Does the gearbox oil is above the shaft level when it is normally service to the right qty or just below?
is it hard to change this seals? can this be done with only removing the axle?
thank you

Answer
The gear oil level is normally even with the fill plug.  This will be above the level of the axle seal.  Although the seal is designed to seal when the fluid level is above the seal, overfilling the transmission can cause pressure in the transmission and hence a leak at the weakest point.

If the leak is at the left axle, you should check to make sure the axle is properly locked (clipped) into the transmission.  If it isn't it'll push out and the fluid will leak out of the transmission there.

You can replace the seal by removing the axle from that seal, but it'll be difficult to get the new seal installed evenly without the special tool that fits the seal and the differential in the transmission.  I've damaged many seals trying to do this when I didn't have access to the tool.  With the tool, it's always easy and simple to do.