So I have a lil bit of fluid that drips from my NP435 and 205 t/c. Thinking of just getting rebuild kits for them to overhaul, or should I just find where the leak is and fix it. Also, what type of oil do I out in them? I am assuming a gear oil, just not sure of any specifics.

 

I would find the leaks first and fix them. It's probably the input seal in the transfer case. Right where the transfer bolts to the transmission. In my experience that's where most leaks have occurred. As far as oil I ran 80/90 weight in both my np435 and 205 transfer.

 

Do they need a complete overhaul? Might as well if you have to pull them to get to the leaking seal. Especially if you have to slit them.

But if it is just a output flange seal, that is a quick deal. X2 on 80/90.