The Dana 20 is found in 1962-1979 Jeep vehicles. It is also found in IH vehicles as well as a limited run of GM trucks in the early-mid 1970's. The Dana 20's design was outstanding and remains one of the strongest and most refined of all the popular transfer cases.
Comments: It came stock in my '79 CJ5, it's slightly worn so it has the 2wd low mod. Search you'll understand. The only complaint I've had is one of the press in caps on the rear of the t-case popped off and basically dumped all the fluid out. No biggie I just dimpled the cap a little and installed it with thread sealer, a few taps with a hammer and it's good to go.