a great set of do-it-yourslef instructions for a transfer case encoder motor on a Ford Truck
.

very easy instalation... 3/8 drive socket wrench and 10mm socket needed(drop light may be needed as well as a rubber mallet). there are 4 bolts holding this unit on. one bold holds the back brace on and 3 hold the housing on. there is one plug.
step 1 disconnect plug and swing it out of your way. to disconnect connector from unit depress tab on back and slide downward.

step 2 remove one 10mm bolt from back brace.

step 3 remove 3 bolts from motor housing to transfer case.

step 4 unit can be pretty hard to get off( depending on how long it has been on) so you may need to tap it with a rubber mallet.

Installation
step 1 match the unit female to the transfer case male and slide on.

step 2 line up your bolt holes and start bolts.(you may want to put some thread lock on them to ensure the do not back out)

step 3 tighten all 4 bolts to about 40-50 inch pounds.
step 4 connect the connector back and slide onto the new unit.

now you should be ready to try it out. double check your work and follow your instructions for 4x4 engagement.

...read the full guide with pics here