Ok, I have an 03, so i have an open differental...so, do I change the fluids in it?

Feel free to flame, lol.

 

Yes, you will want to go to your local mitsu dealer and buy some fuild for your transfer case or you could search some of the vendors sites on here and purchase it from them.

 

So, transfer case and front diff are the same unit?

 

No, they are two different things. Transfer case does exactly that, it transfers power to the rear differential. The front differential is in the transmission (I'm sure you've heard the term "LSD-limited slip differential", the front diff is just an open diff instead of an LSD type which IIRC the rear diff is a LSD type).

To change the fluid around your front differential you would have to change the transmission fluid. And since you're already doing that, it wouldn't hurt to do the transfer case and rear diff at the same time with the appropriate fluids.