Hy Farmone, a lot depends on what happens when you attempt to drain the lube out of the transmission and rear axle. Both components could be lubed with 90wt oil, at low temperatures pretty thick stuff. When you drain each, drain through a strainer, note the colour of the lube, and see what kind of chunks get hung up in the strainer. If the transmission is a four speed you can remove the top cover and wash down through it with some kerosene or diesel, for the rear axle depending on the year, you could remove the rear cover and wash down/inspect from that vantage point, hope that helps.
