Was doing routine maintenance on my 1983 GMC, half-ton, 4-wheel drive p/u truck. Loosened the big "fill-plug" on the transfer case and about a pt. of milky white fluid poured out. I'd like to drain this old ATF out and fill with new ATF. Is there a drain plug on the transfer case, and if so, where is it located? How mant pts. of ATF does a transfer case hold and is regular Dextron III ATF the type lube to use in this style transfer case? Anything else I need to know about changing lube in a New Process transfer case? Thanks.