That ratchet is covered under warranty. Most "government" industrial tools are marked. The reason the don't bring as much is because they made them for 25 or so years. And they made a bunch of them.
I have 3 of them, all I can say is they all have rust and no one makes replacement panels, the best advice is that older ih's have weak cam bearings make sure that it has good oil pressure when warm. They are a lot of fun to have...
The 100 tooth ratchet have the teeth in the housing so they won't interchange, and the 80s have a totally different housing as well. Hope that helps.
Jack