Turn out fixing bolts and remove the pump transfer case assembly (4).
Rinse all components, suede and wipe dry with compressed air.
Installation is in the reverse order - make sure that the protrusion of the carrier plate deployed bolt heads up the pump assembly is aligned with the flattened shaft - if necessary, turn the last few times, - pump assembly should fully take on the drive shaft.
Finally, check the transfer case for signs of leaks.