The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 02-16-2014, 09:42 PM   #1
TwoFiftyShifter
Registered User
 
Join Date: Nov 2008
Location: Gwinnett GA
Posts: 1,803
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?
__________________
1982 K10 SWB
1987 V20 - Sold - Doh!
TwoFiftyShifter is offline   Reply With Quote
Old 02-16-2014, 10:27 PM   #2
buddy_1
Registered User
 
buddy_1's Avatar
 
Join Date: Dec 2013
Location: Humble, Texas
Posts: 185
Re: 12 bolt rear ratio

I'd say check your count again, they don't show that ratio in the catalog.
__________________
I know the "VOICES" aren't real but they have some great ideas.
1978 GMC Sierra Classic C25
1983 Datsun 280ZX Turbo
1997 Chevy Cheyenne K2500
1999 Polaris Sport 400
buddy_1 is offline   Reply With Quote
Old 02-17-2014, 01:14 PM   #3
TwoFiftyShifter
Registered User
 
Join Date: Nov 2008
Location: Gwinnett GA
Posts: 1,803
Re: 12 bolt rear ratio

I counted it twice. I don't know the history of the donor vehicle though...
__________________
1982 K10 SWB
1987 V20 - Sold - Doh!
TwoFiftyShifter is offline   Reply With Quote
Old 02-17-2014, 02:19 PM   #4
gchemist
BAD BOW-Silverado XST
 
gchemist's Avatar
 
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
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.
__________________
Gerardo a.k.a. Mad Chemist
Silverado XST videos
gchemist is offline   Reply With Quote
Old 02-17-2014, 02:23 PM   #5
f.monroe
Senior Member
 
f.monroe's Avatar
 
Join Date: May 2004
Location: Caldwell,Tx.
Posts: 3,648
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.
Frank
__________________
Born and proudly residing in a Red State !
f.monroe is offline   Reply With Quote
Old 02-17-2014, 08:58 PM   #6
sierra4x4
Registered User
 
sierra4x4's Avatar
 
Join Date: Jan 2009
Location: Canada
Posts: 308
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.
Attached Images
 
sierra4x4 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:58 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com