tcase is going out

[91rangerxlt]

well my tcase in my 02 edge is goin out, makina helluva racked in 4x4 need to get a new one how hard would it be to swap in a manual tcase the guy i got the truck from ran the tcase outa fluid i filled it up but still no luck sounds like a chain is skipping a tooth. im just gonna get a new tcase. i would like to swap to a manual tcase but if its to hard ill stay with auto. how much would a used one cost.