As far as elimination goes, if it's got Full Float rear axles in the rear, it won't be 3.42 gears since FF didn't have a nothing close to 3.42. It could be 3.23 sicne FF has a 3.21 ratio, but being 4x4, I'd say you're going to have 3.73 or 4.10 ratio, and even though 4.10 is most common, it could be 3.73 since the 82 had a 6.2 Diesel motor. Those motors didn't like high RPM at all and if GM were smart, they did 3.73 instead of 4.10 but you never know. Can you get the axle code off the axle tube? Or Count it as you just suggested. But if it's a Pull it yourself lot, I'd damn sure hurry up. That 8 lug stuff goes fast.