@bob-remm Bob, are you trying to determine the ratio of a differential that is in a car?

Mike

@35mike ,

I am doing just that. I have a few different differentials to choose from. Unfortunately they are buried in the back of an old garage. I could count the teeth on the ring and pinions, however, I would rather not be moving 20 years worth of treasures to get to them. Then removing the covers and sloping old gear oil over somebody else's garage floor doesn't seem like fun either. Taking a picture of the ID numbers sounds like something more within this 78 year old mans capability.

Thanks for the reply.

s 

@bob-remm Bob, If you have a helper you can turn the driveshaft and count the number of turns to get one revolution on a hub. 

Mike

@35mike ,Thanks again Mike.I found the information I needed for torque tube rear ends from 1950-1954. Here is what I found:

Rear axle Identification

The numbers are stamped into the front of the differential carrier, passenger side, between the 8:00 and 10:00 bolts as viewed from front of the car looking aft.

 The first letter will be:

H for 1950

J for  1951

K for 1952

L for 1953

M for 1954

 The next letter will be:

A or B for a 4:11

L or M for a 3:70

S or T for  a 3:55

This differential reads "LL1007" and decodes to a 1953 rear with a 3:70 gear ratio and serial number of 1007

@bob-remm  That is great information. Thanks for posting it.

Mike