Axle Ratio? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ogier · 06-11-2005, 03:34 PM

Greetings,

Any thoughts on what ratio the axle in my 77 1/2 ton might have? It is a corporate 12 bolt if that matters.

The engine/trans combo is 350/th350.

Thanks in advance,

Earl Filter · 06-11-2005, 03:53 PM

No SPID sticker in the glovebox door?

dswancutt · 06-11-2005, 04:48 PM

In typical GM fashion, Not all trucks have the axle ratio listed on the SPID sheet. Both of my 78 and my 79 6 cylinder have it, but my 79 diesel does not, and neither does my uncles 79 diesel. If fact, I don't believe either of his 79 six cylinders have it, nor does the 77 he owns. It is the first place to look, but you will probably end up pulling the rear cover if it doesn't.

Doug

Earl Filter · 06-11-2005, 04:56 PM

Quote:

Originally Posted by dswancutt

In typical GM fashion, Not all trucks have the axle ratio listed on the SPID sheet. Both of my 78 and my 79 6 cylinder have it, but my 79 diesel does not, and neither does my uncles 79 diesel. If fact, I don't believe either of his 79 six cylinders have it, nor does the 77 he owns. It is the first place to look, but you will probably end up pulling the rear cover if it doesn't.

Doug

I've never seen a SPID without an axle code, even if it doesn't spell out the ratio for you. But, then again, I've never seen every GM vehicle, either! I know they do some weird stuff on a whim it seems.

dswancutt · 06-11-2005, 05:14 PM

The only thing I can think of is that it is only listed if you have an optional rear end ratio.

Both of my 78's have 3.73 and my 79 6 cylinder is a 3.40.

Doug

TrainD5115 · 06-11-2005, 08:48 PM

You can try looking here. My sticker does not list a ratio either. http://67-72chevytrucks.com/vboard/s....php3?t=157669

06-11-2005, 03:34 PM	#1
Ogier Chopper/Painter Join Date: Jul 2004 Location: Medford, Or. Posts: 284	Axle Ratio? Greetings, Any thoughts on what ratio the axle in my 77 1/2 ton might have? It is a corporate 12 bolt if that matters. The engine/trans combo is 350/th350. Thanks in advance, __________________ With regards, Ogier 1969 Chevrolet C20 - Resto-Custom started!!!

06-11-2005, 03:53 PM	#2
Earl Filter Registered User Join Date: May 2005 Posts: 212	No SPID sticker in the glovebox door? __________________ Real Name - Brandon Current Vehicles: 1977 C20 Silverado 454/TH400 3.73s 1989 Jaguar XJ6 in the middle of an LT1/4L60E swap

06-11-2005, 08:48 PM	#6
TrainD5115 North Coast, baby! Join Date: Jun 2004 Location: Toledo, OH Posts: 437	You can try looking here. My sticker does not list a ratio either. http://67-72chevytrucks.com/vboard/s....php3?t=157669 __________________ Brad 79 Scottsdale C20 350/350 3.73's Still running full CA smog gear! Last edited by TrainD5115; 06-11-2005 at 08:49 PM.

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06-11-2005, 04:48 PM	#3
dswancutt Registered User Join Date: Jul 2003 Location: Franklin, NE Posts: 387	In typical GM fashion, Not all trucks have the axle ratio listed on the SPID sheet. Both of my 78 and my 79 6 cylinder have it, but my 79 diesel does not, and neither does my uncles 79 diesel. If fact, I don't believe either of his 79 six cylinders have it, nor does the 77 he owns. It is the first place to look, but you will probably end up pulling the rear cover if it doesn't. Doug

06-11-2005, 05:14 PM	#5
dswancutt Registered User Join Date: Jul 2003 Location: Franklin, NE Posts: 387	The only thing I can think of is that it is only listed if you have an optional rear end ratio. Both of my 78's have 3.73 and my 79 6 cylinder is a 3.40. Doug



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