F-12 tranmisson

I have 2 Farmall F-12, I want to know how you can tell if 3rd gear has the faster road gear in it. Because I have heard of a 7mph 3rd gear instead of the 3 1/2mph gear. If there are any stamped number in the casing or any casing number"s on the housing what would they be and where. Thanks
e-mail [email protected]
phone # 1-606-928-3153

(quoted from post at 13:22:48 09/26/08) I have 2 Farmall F-12, I want to know how you can tell if 3rd gear has the faster road gear in it. Because I have heard of a 7mph 3rd gear instead of the 3 1/2mph gear. If there are any stamped number in the casing or any casing number"s on the housing what would they be and where. Thanks
e-mail [email protected]
phone # 1-606-928-3153

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Howdy! I've only seen the slow one; or on F-20s the add on; so, I'm no help there. But noticed your name - you don't by chance farm a few acres in Minnesota with a Minneapolis U? If not, my mistake please disregard; else say hi to your Dad from me!

Mhorn,I lucked out and my first F12 has a 7mph road gear,On the back of the tranny case just above the pto shaft theres a flat embossed plate and on the very left of the flat plate theres a letter stamped on it,very hard to see,and you need to sand very hard to find it,I forget what letter it is,I think F is for the 3 3/4 mph.The new farmall book has this information in it

jimmy

My Dad's 1933 F-12 has the 7MPH transmission, Nebraska Cowman once said how to tell if it has the higher speed gears, you could ask him by emailing him at [email protected]

Andy

I am not trying to be smart or anything, but how about following it with a car? Car speedos have error, but they should be good enough to tell the difference between 3 and 7mph. If they don't run, jack up one side an inch or so and put a chalk mark on the rim or tire. Put it in 3rd gear and with the coil wire pulled and the fuel shut off, count the number of crankshaft revolutions for that mark to make one revolution. That is your gear ratio. You can check with the ratio in the book, or actually calculate your groundspeed with the following formula:
Max Engine RPM divided by gear ratio multiplied by tire outside diameter in inches multiplied by 0.002975 equals max ground speed in mph.

The original specs for F-12 on STEEL said 4 MPH for third gear. On 40" rubber, I believe the speeds should be about the same as the original 54" steel wheels. On 36" rubber (fairly common in the early days of putting rubber on these tractors), third would be a bit slower. I spent years and years and years on three F-12s with the standard transmission, and I can tell you that (I'm 5" 7") I could walk behind the tractors at a fast walk. I never tried this behind a tractor with the 7 mph third gear, but I think it would require a good jog to keep up with one. The normal third gear feels pretty slow. The 7 mph speed is calculated at full-load rpm, so probably at idle speed the tractor would be a little faster--maybe 8 mph. Even 8 mph sitting up there in the open feels "fast" compared to the original speeds. I now have a more modern tractor that will do about 8 mph in one of its top gears, and it definitely feels like you're moving over the ground--I can even feel the wind in my face! Sorry this is so vague. If there are other tractors to compare with, you can run yours along side these (and probably a number of others--most tractors from the thirties had working speeds of 3 and 4 mph or thereabouts): Farmall A, third gear is just under 5 mph. Farmall F-20, third gear on 36" rubber is probably about 4.5 mph. Farmall H, third gear is just over 4 mph.