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#1 |
Registered User
![]() Join Date: Apr 2014
Location: Waterford MI
Posts: 155
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72 rear axle ratio question
Hi Guys
My truck has a 72 frame and components, took the rear axle cover off to find the gear ratio. It appears to be a 4:11. This is a part number off the ring and pinion. part number is #381778 11:4 GM Seems that a 1/2 ton two wheel drive long box would come with a 3:73 rear end. Mike |
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#2 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,631
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Re: 72 rear axle ratio question
Different gear ratios could be ordered back in the day, not to mention changed by previous owners. Best way to know for sure, with the cover off, is to count the teeth. Divide the teeth on the ring gear by the teeth on the pinion gear to get the exact ratio.
__________________
- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#3 |
Registered User
Join Date: Dec 2012
Location: Fontana, Ca
Posts: 228
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Re: 72 rear axle ratio question
You could jack it up, spin the drive shaft 1 revolution and see how much the wheels spin.
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#4 |
Registered User
Join Date: Apr 2011
Location: Mustang, Oklahoma
Posts: 2,806
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Re: 72 rear axle ratio question
If you look a little closer I bet it says 381778 11:41GM on the ring gear. This means 11 pinion gear teeth, 41 ring gear teeth. 41/11= 3.73. The original gears had these part number/ratio stamping.
__________________
Dan <---(my name) 67 SWB C10 project "GEORGIA"-59 Brookwood 2dr wag...Next project-03 Tahoe 4x4 5.3 family ride-07 Hondur Accord, commuter car |
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#5 | |
Registered User
![]() Join Date: Apr 2014
Location: Waterford MI
Posts: 155
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Re: 72 rear axle ratio question
Quote:
Mike |
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