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Old Jan 23, 2007 | 05:59 PM
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Default Speedometer Gears
What speedometer gears go with what 65-79 differential ratios and where can you buy them?
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Old Jan 23, 2007 | 06:19 PM
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Originally Posted by Lightweight 001
What speedometer gears go with what 65-79 differential ratios and where can you buy them?
Auto or manual ?
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Old Jan 23, 2007 | 06:27 PM
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Rear Color Teeth Tranny
2.733 Blue 17 M40
3.083 Blue 8/17 M20/M40
3.363 Yellow 7 M20
Brown 15 M40
3.55 Yellow 7 M20/M21
Brown 15 M40
3.70 Yellow 7 M21
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Old Jan 23, 2007 | 06:27 PM
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manaul, but I am interested in knowing the info on the autos as well...
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Old Jan 23, 2007 | 06:28 PM
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M20 and M21 are manual
M40 auto I think
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Old Jan 23, 2007 | 06:34 PM
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What about a 3.90 or 4.11?
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Old Jan 23, 2007 | 07:07 PM
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Originally Posted by Lightweight 001
What speedometer gears go with what 65-79 differential ratios and where can you buy them?
Here's lots of gears and info at this web site. Pages below are from GM parts manual.
http://www.transmissioncenter.net/sp...n_______va.htm







Last edited by Duke94; Jan 23, 2007 at 07:12 PM.
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Old Jan 27, 2007 | 08:42 PM
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The last owner installed a used speedo cable that made noise and was way off. Got a new cable and gear from Zip.
http://www.zip-products.com/Zip/dept.asp?dept_id=2360
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Old Jan 27, 2007 | 09:58 PM
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Originally Posted by RadicalPursuit
M20 and M21 are manual
M40 auto I think




Correct

M40 = TH400
M38 = TH350
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