This operation can be performed on the transmission without any need to be detached from the vehicle. Starting with positioning of the car over a pit or lifting it with aid of jacking to provide access to the transmission, and providing support with jack stands. Secondly, remove the drive shaft from the work by delinking it from the transmission. In order to remove the seal, dent it and try to use it as a lever with the help of a screwdriver or a chisel. Take some jointing compound and place it on the outer perimeter of the new seal then using a piece of tubing as a drift; force it into the position. Last, but not the least, replace the driveshaft back and check the level of the fluid in the transmission unit.