Rear end numbers - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dewey Clines · 03-19-2013, 09:41 PM

Help! I've looked everywhere for a Chevy Truck rear end decoding list to no avail. I'm sure this has been discussed in some past thread so here goes
I have a 12 bolt rear end that is supposed to be out of a 76 K5 Blazer that I would like to replace the 10 bolt in my 65 Suburban. The numbers on the axle tube are K BH 303W71. I can't find this anywhere - so can anyone help?
Thanks
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gchemist · 03-20-2013, 07:08 AM

You will not find gear codes unless you have RPO codes from the Blazer. 12 bolts come in different ratios. Since the axel is out, pull the cover off. Read the numbers stamped on the ring. How did your Sub end up with a 10 bolt?

I swapped a 10 bolt for a 12 bolt in my 83. I like the bigger stronger axel.

andrewmp6 · 03-20-2013, 07:45 AM

To tell the gear ratio with out opening it up http://www.how-to-build-hotrods.com/gear-ratio.html As far as what its from i don't know but someone else might.

Dewey Clines · 03-20-2013, 10:45 PM

Thanks for the feed back. I'll pull the cover off the pumpkin this weekend and see what's inside. What I was hoping to find is someone who has access to a list of the codes for the GM rear end numbers stamped on the axle tube on the upper passenger side.
I'm not sure how a 10 bolt got on my 65 Sub. Mines a GMC with leaf springs so that maybe what was factory installed.
Anyway if anyone knows of a decoding list I would sure like help finding it.
Dewey
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Dewey Clines · 03-22-2013, 10:42 PM

Took the cover off and located the ring gear numbers 11:41 or 373 ratio. Still have not been able to find any link or site that could offer anything on decoding the axle tube numbers. If anybody comes across anything please let me no.
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gchemist · 03-23-2013, 07:50 AM

You can decode some it here: http://www.crankshaftcoalition.com/w...identification

Dewey Clines · 03-23-2013, 12:33 PM

Thanks saw that one too. Nothing really on mid 70's K5 or trucks. I've spent hours going from Camaro, Nova, NastyZ28, G3 and others to find nothing helpful. After all the links I've looked at I thought someone would have put something helpful in one of them. But sadly not.
Thanks again I'll keep looking.
Dewey
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03-19-2013, 09:41 PM	#1
Dewey Clines Registered User Join Date: Jan 2013 Location: Vista, CA Posts: 33	Rear end numbers Help! I've looked everywhere for a Chevy Truck rear end decoding list to no avail. I'm sure this has been discussed in some past thread so here goes I have a 12 bolt rear end that is supposed to be out of a 76 K5 Blazer that I would like to replace the 10 bolt in my 65 Suburban. The numbers on the axle tube are K BH 303W71. I can't find this anywhere - so can anyone help? Thanks Posted via Mobile Device

03-20-2013, 07:08 AM	#2
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: Rear end numbers You will not find gear codes unless you have RPO codes from the Blazer. 12 bolts come in different ratios. Since the axel is out, pull the cover off. Read the numbers stamped on the ring. How did your Sub end up with a 10 bolt? I swapped a 10 bolt for a 12 bolt in my 83. I like the bigger stronger axel. __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

03-20-2013, 07:45 AM	#3
andrewmp6 Registered User Join Date: Jan 2009 Location: Louisville,Ky Posts: 5,811	Re: Rear end numbers To tell the gear ratio with out opening it up http://www.how-to-build-hotrods.com/gear-ratio.html As far as what its from i don't know but someone else might.

03-20-2013, 10:45 PM	#4
Dewey Clines Registered User Join Date: Jan 2013 Location: Vista, CA Posts: 33	Re: Rear end numbers Thanks for the feed back. I'll pull the cover off the pumpkin this weekend and see what's inside. What I was hoping to find is someone who has access to a list of the codes for the GM rear end numbers stamped on the axle tube on the upper passenger side. I'm not sure how a 10 bolt got on my 65 Sub. Mines a GMC with leaf springs so that maybe what was factory installed. Anyway if anyone knows of a decoding list I would sure like help finding it. Dewey Posted via Mobile Device

03-22-2013, 10:42 PM	#5
Dewey Clines Registered User Join Date: Jan 2013 Location: Vista, CA Posts: 33	Re: Rear end numbers Took the cover off and located the ring gear numbers 11:41 or 373 ratio. Still have not been able to find any link or site that could offer anything on decoding the axle tube numbers. If anybody comes across anything please let me no. Posted via Mobile Device

03-23-2013, 07:50 AM	#6
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: Rear end numbers You can decode some it here: http://www.crankshaftcoalition.com/w...identification __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

03-23-2013, 12:33 PM	#7
Dewey Clines Registered User Join Date: Jan 2013 Location: Vista, CA Posts: 33	Re: Rear end numbers Thanks saw that one too. Nothing really on mid 70's K5 or trucks. I've spent hours going from Camaro, Nova, NastyZ28, G3 and others to find nothing helpful. After all the links I've looked at I thought someone would have put something helpful in one of them. But sadly not. Thanks again I'll keep looking. Dewey Posted via Mobile Device

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