I recently purchased an 81' blazer that was all stock. Now, it has a rebuilt motor and edelbrock manifold, headers, dual exhaust, and emissions equip. removed. When I put in in 4lo I get a whine from the transfer case. I was just wondering if this is normal or not? I wanted to check the fluid level but was not sure how or what to oil to but back in if I did change it. I was looking @ the T-case the other day and there are too plugs on the back side. One up high and one at the bottom. I was wondering if these would be the drain/fill plugs? Also, what oil do you put in differentials? I am going to change those as well because I don't know what the last time the PO did that. Any help is appreciated! /forums/images/graemlins/ears.gif P.S. What type of T-case would I have? NP203?