It should have a Dana 30 front axle and AMC Model 20 rear axle (probably with 2 piece axle shafts
). Probably has a Dana 20 transfer case or maybe Qtrac? (can't remember off the top of my head what years Quadratrac was offered). If the rear diff is centered it'll be a Dana 20. If it's a 6 banger it's probably a 258 AMC motor. Can't remember if 304s V8s were offered in 78. Tranny could be a T150 3 speed, or maybe (rare) a T18 4 speed. Might be easier for you to take a look, write down some notes or better yet, take digital pics, and post them back up here for dissection. My first Jeep was a 78 CJ7. Good luck!