Just the low range is interchangeable but the cases are different (rear output), double check that but I remember way back when these gears first came out (Az Crew member Lordtrunks helped pay development costs) they made 4 cylinder gear set and then went into development of the V6 case they ended up being the same. Double check that but i think the only difference is Auto vs Manual.

1999 Montero SAS'd on Kings and stuff

1998 Montero trying to get a V8 Swapped