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Old 02-16-2014, 09:42 PM   #1
TwoFiftyShifter
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12 bolt rear ratio

Blew the rear end out of my 84 Silverado. My right rear wheel almost fell off going down the road and there is a 5 inch hole in my diff cover.

I have a replacement 12 bolt from a 79K10. I popped the diff and counted 47 ring and 16 pinion. Is it just me, or is that a lot of teeth? The math comes out to 2.94. My Silverado is 3.08. I'm hoping this read end is 308 also. Any tips?
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Old 02-16-2014, 10:27 PM   #2
buddy_1
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Re: 12 bolt rear ratio

I'd say check your count again, they don't show that ratio in the catalog.
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Old 02-17-2014, 01:14 PM   #3
TwoFiftyShifter
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Re: 12 bolt rear ratio

I counted it twice. I don't know the history of the donor vehicle though...
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Old 02-17-2014, 02:19 PM   #4
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Re: 12 bolt rear ratio

46/15=3.07 ~ 3.08
Count the gooves instead of teeth.
The big ring will have number stampped on it.
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Old 02-17-2014, 02:23 PM   #5
f.monroe
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Re: 12 bolt rear ratio

47 and 17 is a 2.76. That was a factory ratio offered. I haven't heard of the numbers you listed. If it is indeed as you counted it then you should be close enough.
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Old 02-17-2014, 08:58 PM   #6
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Re: 12 bolt rear ratio

The number of teeth should be stamped on the ring gear. The one shown is 14-43 which is 3.07.
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