I could be wrong but unless there's a federal law requiring that info on tractors I don't think you're not going to find anything. Tractors don't fall under the DOT. That's probably good because if we had to pay for airbags and all the other safety stuff on tractors, the price would probably skyrocket. I can already imagine the Onstar commercial.
Tractor owner: "I've gotten stuck."
Onstar: "Sir, you don't seem to be on a highway."
Tractor owner: "That's correct. I'm stuck in a field."
Onstar: "You're off the road? Are you OK? I'll dispatch someone immediately."
Tractor owner: "Don't do that. I just need you to call my wife and tell her I'm going to be late for lunch."
FWIW, I can remember when JD had to replace the axles on some of their CUTs and I don't believe there was a recall. If you complained, you got a new axle. If you didn't ... who knows what happened. The feds didn't care.