I just picked up another 77 F250. I was looking at the door tag. I wanted to know what gear ratio it had. It has code 22? What is that? I cannot find anything in my literature, shop manuals, or the internet on what that would be. The closest thing I can find would be a Dana 70 with a 4.88 ratio in a 1970 F350. The only thing I know for sure on this axle is that it is non-trac lok, has close to a 3.07 ratio, and it is a Dana 60 (or 61). The tag on the axle is pretty rough, but I'm pretty sure it is a 60. Thanks for the help.

 

You just answered your own question...

1977/79 Axle code 22 = Dana 61 open rear differential, 3.07 ratio.

1974 ONLY - Dana 70 open rear differential, 4.88 ratio.