| LarryK | -- 09-25-2014 @ 4:55 AM |
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I have a 1939 Deluxe Tudor which I believe is original as regards the engine (85 HP), transmission, and rear axle. I cannot find any numbers stamped on or near the differential housing indicating the number of teeth on the pinion and ring gear. Absent these numbers, can I assume that the axle ratio is the standard for this car, i.e., 3.78:1? Thanks Larry
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| David J | -- 09-25-2014 @ 6:09 AM |
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The marking will be on the bottom front rib of the banjo just behind the torque tube . My stuff normally has 9-37 for 33-34 . Yours will be different but that is where it is . I can get pics of this if needed . Also look on the speedo gear turtle as those are marked with 21 , 19 , etc and will tell you also . You can also turn the motor over by hand and see how many revolutions it takes to turn one jacked up rear wheel 1/2 turn . This is of course with the tranny in high and if you have a Columbia leave it in drive , With a 3.78 you should get just a tic over 3 3/4 turns of the motor to turn ONE WHEEL exactly a half turn . If you do BOTH rear wheels just over 3 3/4 turns of the motor will get you a full revolution of BOTH rear wheels . Diff gears are 2-1 and that is why you get different readings with one or two rear wheels turning. One wheel up is easiest and if you get just over four turns you have 4.11 and just over 3 1/2 turns you have 3.54 . Simple stuff . Dave
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| supereal | -- 09-25-2014 @ 12:06 PM |
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The numbers 9-37 would indicate a 4:11 ratio, with a 21 cast into the speedo drive on the torque tube. This is not a good ratio for overall driving. A 34-9 , which is for 3:78, is better. The speedo srive would have 19 on the top. Ford used 4:11 in vehicles sold for hilly country, with 3:78 being the most equipped type. a 39-11 would indicate 3:53, and a truck axle may have 41-9 stamped for a 4:55. The numbers are usually there on the bottom of the pinion web, but may not be true if the gears were replaced at some time. The numbers can be hard to find, as they are usually covered with dirt, etc.
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| flatheadfan | -- 09-26-2014 @ 5:37 AM |
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Larry- Here is a view that everyone is referring to. It is on the bottom center rib of the axle: Hope this helps. Tom
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| LarryK | -- 09-26-2014 @ 9:47 AM |
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Wow. There they are, right where you all said they would be. 9-34. Very faint. Henry must have been getting a little feeble when he stamped these in. I don't think the CIA could have found them. Thanks everyone. Larry
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