DAVE - Your exactly correct, lots of special tools needed to make gears. I was a production scheduler in a gear machining dept. at FARMALL in Rock Island. I thought I put all this info somewhere here before, maybe on Facebook, But a small gear like a creeper gearbox planet gear could best be made from cut-off bar stock, have to bore the center hole, then turn the OD to be concentric. Then hob the gear teeth, we had a long row of small Barber Coleman hobs at FARMALL that we made oil pump gears on that were similar to the creeper gears. Then the gears would have to have the proper involute tooth design machined into the teeth on a gear Shaving machine. The involute shape distributes the load over the gear tooth surface so the teeth don't chip out. Then comes heat-treat for wear resistance. There's lots of 3-place decimals on dimensions on gear prints. The department I scheduled was right next to FARMALL's gear inspection lab. The first couple gears of every batch went into the lab for approval before they ran any more. We. I've had 2-3 guys in our dept just to set-up the gear hobs and shavers, and they stayed busy!
I've visited a couple companies years ago that specialized in machining gears, one made a set of herringbone gears, had two rows of angled teeth on each side of the gear face at about a 45 degree angle, the large reduction gear about 2-1/2 feet diameter, and the 6 inch diameter drive pinion.
Mitsubishi makes wire electro-discharge machines, they make an electric spark between the wire to the steel blank that erodes away the steel, making a real precise part with good surface finish out of prior heat-treated material. Saves lots of special machines and tooling. It's a slower machining process but can run unattended 24-7, just needs someone to load new blanks into the machine.
You will probably need the DANCO print to get all the dimensions and tolerances of the gears. I don't know if Danco may still be in business or been bought out by someone. IH probably had a blue print of the gears to inspect incoming parts they bought for service parts, I'm not sure how easy MTD would be to deal with getting hold of a print.