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MF10/12G transaxle and varidrive ratios

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Posted November 26, 2010 - 11:49 PM

I am working on the mathmatical side of doing a 4x4 conversion on an MF10/12. It will be getting a much heavier powertrain than the original. So, I have to figure out some numbers first.

I have this much so far 1st/1st @1500 RPM (idle) is a 256.7:1 crawl ratio, 5th/4th @3600 RPM is a 27.68:1 crawl ratio. Anybody know the gear spread in the transmission and the spread in the varidrive? None of the manuals I have cover this in much detail.

I need to figure this out to find a rear axle ratio that works. Then using that figure the front axle ratio necessary (since the front tires are smaller). then go back and figure out the basic reductions necessary to make a Ford model A transmission work as the main transmission. The transfer case will be a chain drive/sprocket homejob. Heckendorn used the model A transmission on thier mowers, is was originally behind a 40 HP motor and is tiny.

I am planning on using...

Dana 25/44 front axle narrowed or 9" ford center with dana outers or possibly a gear reducer built into a front axle
GM 5200#rear axle narrowed (10 1/8 ring gear)
Ford Model A transmission
homemade chain driven transfercase
Lister Petter diesel or kohler 2 cylinder about 20HP
possibly going to turbo if it's diesel

If you can't tell I'm boycotting China/Japan stuff on this project, I think I'll have to run over to the co-op and weigh it when it's done!:D

It will be like a 4wd panzer on steroids

#2 tractormike OFFLINE  


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Posted November 27, 2010 - 07:20 AM

I don't know the ratio's that you need but your project sounds like it will be a major piece of iron when you are done! That should make for a very interesting build.

#3 caseguy OFFLINE  


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Posted November 27, 2010 - 08:35 AM

You could make your head hurt a little less and use the same size front wheels as the rears. Just a thought.