1950 f1 rear end

[bergie]

I have been trying to figure out which of the possible ratios I have in my truck and of course everyone says there is a metal tag on the case. I now have the bed of the truck off and can see every bit of the case. No metal tag. I see an area that looks like there could have been a tag at one time. I am not the first person to try to make a ‘driver ‘ out of this truck. Any ideas on how to know what the ‘guts’ are in this truck? Thanks for your ideas, Bergie.

[deuce5wndw]

Surest way would be pull the cover and count the ring and pinion.

[Ford Freak]

My '52 F1 has a tag on the inside of the glovebox door. It shows paint code, transmision code, and 3:92 rear axle ratio. Not sure if the '50 F1's had that or not? - F F

[cadillac512]

Hi bergie-
With the bed off it'll be pretty easy. Jack up one rear wheel so you can turn the tire. Mark that tire top or bottom so you can count the rotations. Now mark the driveshaft as well. Have a helper count the turns of the driveshaft as you turn the tire ten full revolutions.


If the driveshaft turns 17.5 times it will be a 3.50 ratio...20.5 times will be 4.10 and so on. Just multiply the driveshaft turns by two since only one wheel is turning, which halves the count on the driveshaft.


IF it has a locking rear end you'll have to raise both wheels and in that case you won't multiply the turns by two.


Terry

[Flathead Fever]

There is different way to do this. Oneway is to put a chalk mark on the rear tire and one on the pinion flange. With both rear tires on the ground so that they both roll the same distance, roll the truck forward one full tire revolution while counting the rotation of the pinion flange. If the pinion flange turns 4 times for one tire rotation you would have 4.00:1 gears. 3 1/2 turns, 3.50:1 gears. You will be able to get a pretty accurate ratio. It won't be exact, but you can use the number you come up with and compare it to what factory gear ratios were available . The closest one to your number will probably be the one that's in there.

Like deuce5wndo said. The only way to know for sure is to divide the pinion teeth into the ring gear teeth and you would need to open up the rear end to count the teeth.

[TJ]

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Originally Posted by Ford Freak

My '52 F1 has a tag on the inside of the glovebox door. It shows paint code, transmision code, and 3:92 rear axle ratio. Not sure if the '50 F1's had that or not? - F F

Bingo, that is the correct answer unless the rear end was changed at one time.