One more note on tractors be it Deere or IH. This is my opinion but for haying I would stay away from any with a powered front axle. This in the age tractor you are looking at.
Deere used what they called Front Wheel Assist. As long as you used it as an assist it worked OK. By that I mean if you only used it in the spots in the field you needed it and left it off the rest of the time, I had good luck with it. If you used it like a true MFWD, the oil would heat up and the system would have so much slip it wouldn't work. Basically it would pull you deep into mud hole and on the other side the wheels when they hit solid ground would not spin enough to pull you out. Good in theory and works on road graders, combines etc. Not very good on a tractor. These were on 20-40 series Deeres.
IH used at least 2 and I think 3 different axle suppliers, Elwood and Coleman, maybe one other. One system didn't use planetary gears, but a direct drive system. I used one once that the owner told me if I forgot to turn it off and back up, or drove very far down the road with it on it would snap the drive shaft. The 2nd did use planetary axle, from what I have read and again one owners own experience it wasn't very durable. The last system is very similar to what is used today. This system is suppose to be the best, but turning wasn't very good. These systems were on 06, 56, and 66 series tractors as a add on system.
I have driven IH with all 3 axles and if you need it, there better than not having (and better than Deeres), but if you don't not worth it IMO.
Again, just my $.02 on it.