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02-10-2021, 06:36 PM | #1 |
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rear differential ratio
just bought a 34 cabriolet and i would like to know what the rear end gear ratio is. is there a way to tell without opening the the rear end and counting the teeth
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02-10-2021, 06:45 PM | #2 |
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Re: rear differential ratio
The ring and pinon numbers are supposedly stamped on the bottom of the center section of the rear end. Notice I said supposedly because I can't find any numbers on the rear end in my '39 p/u although I've tried on several different occasions.
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02-10-2021, 07:22 PM | #3 | |
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Re: rear differential ratio
Quote:
3.54 = 11/39 3.78 = 9/34 4.11 = 9/37 The number of teeth on your ring gear should match ONE of the last numbers in each of the above. DD |
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02-10-2021, 07:33 PM | #4 |
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Re: rear differential ratio
Does it have a starting handle? (crank handle)?
If so you can jack up one rear wheel, put it in top (high) gear, and turn the handle until the raised wheel has turned exactly 2 revs. The number of turns of the crank handle equals the axle ratio. The possibilities are listed above so it should be easy to work out which one you have. Most likely is 4.11 This video may help. https://youtu.be/bkvp3Fq21ZM Mart. Last edited by Mart; 02-10-2021 at 07:49 PM. |
02-11-2021, 12:12 AM | #5 | |
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Re: rear differential ratio
Quote:
With the spark plugs out!
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02-11-2021, 07:10 AM | #6 |
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Re: rear differential ratio
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02-11-2021, 08:03 PM | #7 | |
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Re: rear differential ratio
Quote:
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02-11-2021, 09:33 PM | #8 |
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Re: rear differential ratio
That's true with both wheels up (and they turn together). With one wheel fixed the spider gears come into play.
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02-11-2021, 09:38 PM | #9 |
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Re: rear differential ratio
What about checking the number on the turtle? Will that tell you the ratio?
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02-11-2021, 11:40 PM | #10 | |
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Re: rear differential ratio
Quote:
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02-12-2021, 06:25 AM | #11 |
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Re: rear differential ratio
Thanks for the chart. That explains quite a bit. I have seen mostly 3.78 rears and #19.
I keep hoping I will find 3.54 rear some day. |
02-12-2021, 11:21 AM | #12 |
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Re: rear differential ratio
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