How can you identify a Dana 300 from International (IH) 1979-1980 model, for 1979 I heard they are look like D18/20. I've found a 1979 International (IH) in the wrecking yard with an Auto tranny attach but not sure if a Dana 300.
There are a couple ways to distinguis a IH 300 transfercase. 1) And probably the easiest, is that the speedometer connection points towards the passenger side. 2) The tailshaft and front output housings are made of aluminum. 3) Four bolts are used for mounting purposes...some refer to it as a Texas shaped mounting plate. 4) Finally, if you are really lucky, the small metal tag with part numbers will still be attached to the rear of the housing. Doubtful it is still there and readable though!
One other thing, and I could be wrong here, but I believe the IH 300 was used only in 1980 model Scout II vehicles. Good luck determining what you've found!