Ok, so I am a moron. It's 4.3:1 . Helpful hint for the impaired such as myself-if the result seems to be about half of what is expected, rotate BOTH wheels simultaneously and count the corresponding number of rotations of the driveshaft.

How can that be? For every 2.12 revolutions of the driveshaft the wheels rotate once. I don't see how you get around that fact. The ratio is the ratio of the input to the output, or in this case 2.12:1 . Believe me, I wish it were 4.1 but wishing or multiplying by 2 won't make it so. If it were 4.1:1 I would have turned the driveshaft over 4.1 times and the wheel would have rotated once. That's not what happened. That's why I said someone would probably think I was a moron or a lunatic.

Ok, so I am a moron. It's 4.3:1 . Helpful hint for the impaired such as myself-if the result seems to be about half of what is expected, rotate BOTH wheels simultaneously and count the corresponding number of rotations of the driveshaft.

I am hesitant to post this because it makes me look like some kind of moron or lunatic. I raised the rear of the car and marked the position of the driveshaft and driven wheel. I rotated the driveshaft until the wheel made exactly one full rotation. I repeated this a number of times because I couldn't believe it-the ratio as close as I can measure it is 2.12:1 . This could explain why the car was missing the speedometer drive-someone was trying to do some sort of modification to it to make the speedometer read correctly. How in the world did someone come up with the parts to modify the differential in this way? Anybody out there have any ideas? Has anyone heard of something like this before?

Thanks for the information. My transmission does not have OD. I don't know if the rear end is the one which came with the car. That being the case, I guess I'll raise the rear of the car off the ground, mark the driveshaft and wheel positions, and rotate the driveshaft to see what the ratio is for the rear end.

I have a 41 Model 110 with standard 3 speed transmission. The car is a 4 door sedan. It is missing the speedometer drive. Can someone please tell me how many teeth are supposed to be on the gear that is in the missing assembly? Thanks.