NEED 1945 FARMALL M TRANSMISSION SPECS

Patrick Coleman · Feb 8, 2009

I am building and restoring a 1945 Farmall M tractor to be used for tractor pulling. My group or team is actually doing this as our senior design project at Youngstown State University and we are in need of some tranmission specs. We are currently looking for the reduction ratio from engine output shaft to the rear axle, and efficiency of the transmission. If you have good estimates for these or know where to find detailed specs please let me know. I could use the specs from similar models as well if M info cant be found. Thanks

Janicholson · Feb 8, 2009

I teach University classes so the data here is what I would tell the engineers I work with.

There are several transmission options available for Ms. Thus count the constant mesh gear teeth drive and driven, the counter shaft gears for the 4 gears of reduction, and the differential ratio at the pinion/ring. Then factor in the bull gears and pinions ratio in the finals. At the age of the tractor, there may be no other way of assuring the correct answer. You could also take out the plugs and turn the engine in each gear watching the rear axle on one side to calculations, and get close. caseih.com look for parts and service at the top of the splash page, and then start your search her, on the second page. Put in Farmall on the blank box.
Go to M. Select transmission. Very cool content there. JimN

Red Mist · Feb 8, 2009

I used to build 4-speed racing transmissions for roadrace and stockcar teams from back in the 1960's and 1970's. Final drive ratio was very important for each track.
What JimN told you is good advice. I'll add this: Don't forget to [b:2773970e3c]multiply[/b:2773970e3c] each calculated ratio, rather than [b:2773970e3c]add[/b:2773970e3c] them together. Obvious? Yes. Easy to overlook? Yes.
mike

mattofvinings · Feb 8, 2009

I think you might have to get it empirically.

In other words, rotate the trans input shaft by hand, counting, to produce 1 rev of the output shaft.

Regarding efficiency, I'm told that a ring & pinion setup has approx 10% efficiency penalty over a parallel shaft arrangement due to the high sliding friction on the gear faces. Although I have not done my own personal measurements.

To be sure the entire transmission assembly has both parallel shafts and a ring & pinion in it. Arriving at the efficiency empirically would be a trick using a lot of expensive instrumentation.

NEED 1945 FARMALL M TRANSMISSION SPECS

Patrick Coleman

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Janicholson

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Red Mist

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mattofvinings

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