Drain the oil from the transfer case ("Changing the oil in the transfer case")
Disconnect the appropriate cardan shaft from the transfer case
Remove the flange nut after locking the transfer case differential and engaging the gear.
Remove the nut and washer.
Remove the flange from the shaft.
Remove the oil seal with a screwdriver
Apply sealant to the seating surface of the seat in the crankcase under the stuffing box, lubricate the working lip of the stuffing box with oil and press the stuffing box with a suitable mandrel.
Install removed parts in reverse order.
