Need info to change all types of oil in my fourtrax300 1995

Hi

I need some information regarding oil changes for my fourtrax 300FW 1995 . I just bought it a week ago , and want to start a new life with him !!!

That mean change every drop of oil , I already know that I have a front and rear differential full of oil SAE 80W90 , but how about the transfer case just beside the left pedal near the shifter , the mecanichs says it's the same oil as the motor 10W40 , but where's the drain plug ??? I see the fill plug but not the drain plug .

Can anyone help me on this one , i'm new with the forum but it's pretty cool !!!

THANKS