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-   -   Rear Axle Ratio Charts For 1967 - 1972 GM Trucks (https://67-72chevytrucks.com/vboard/showthread.php?t=578793)

LockDoc 05-04-2013 10:35 PM

Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
5 Attachment(s)
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I have saved these from different places so they don't match each other. I saved them as image files and they are all different resolutions and sizes. They really need to be typed into a document file so the size and style of font matches on all of the charts. Unfortunately I don't type good enough to do that so we will try it this way. I just hope they are all readable with the image size restrictions for the board. I think I have them sized close to the maximum that the board allows. Disregard the C14 designation in the '67 chart, it should be C10.

In case someone is thinking Photobucket or some other photo hosting service, I won't do that for two reasons. One, I am not going to sign up for an account & Two, If the photobucket account is ever closed the thread will be worthless because their won't be any pictures of the charts in it, just empty boxes ...

Thanks.

LockDoc

LockDoc 05-04-2013 10:36 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
1 Attachment(s)
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This is the last Chart. It looks like they are mostly readable. A couple of them may be a little blurry.

There is no guarantee of correctness or completeness (is that a word?) in any of these charts

Edit: I might as well add this chart to the thread too.

Rear Axle Ratios

Ratio 2.56:1 - Tooth Combination 41,16
Ratio 2.73:1 - Tooth Combination 41,15
Ratio 3.07:1 - Tooth Combination 43,14
Ratio 3.08:1 - Tooth Combination 40,13
Ratio 3.08:1 - Tooth Combination 37,12
Ratio 3.31:1 - Tooth Combination 43,13
Ratio 3.36:1 - Tooth Combination 37,11
Ratio 3.42:1 - Tooth Combination 41,12
Ratio 3.55:1 - Tooth Combination 39,11
Ratio 3.73:1 - Tooth Combination 41,11
Ratio 4.10:1 - Tooth Combination 41,10
Ratio 4.11:1 - Tooth Combination 37,9

The tooth combination numbers will be found stamped into the ring gear when you take the back cover off.

They may not all be for the trucks.


LockDoc

bruceman1968 05-04-2013 10:50 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Nice job LocDoc, thanks for posting those.

special-K 05-04-2013 11:26 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
This is great! I'm thinking this is for Chevrolet with the 10,20,30 designates. And,I don't see any posi for K/20,only No-Spin. A Dana 60 would have the Power-lok. It shows a 4.11 for K/20,which is the Dana 60,

Hawghauler 05-05-2013 12:44 AM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Thanks LockDoc!

:metal:

I'm sure many people will be less confused. Now there is a place to direct people searching for that elusive code!

LockDoc 05-05-2013 02:20 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
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No problem guys. It might be nice to have them all in one place. I added some info to my 2nd post also.

LockDoc

sambudo 10-27-2013 03:24 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
where can you find these codes on the axel?

LockDoc 10-27-2013 08:34 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
2 Attachment(s)
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Usually on the passengers side axle tube. Just use the first 2 or 3 letters which ever it has.

LockDoc

Keith Seymore 10-28-2013 06:31 AM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Quote:

Originally Posted by LockDoc (Post 6052521)
-
I have saved these from different places so they don't match each other. I saved them as image files and they are all different resolutions and sizes. They really need to be typed into a document file so the size and style of font matches on all of the charts. Unfortunately I don't type good enough to do that so we will try it this way.

Thanks for posting those, Doc.

I'm not offended that the fonts and sizes don't match. Lends credibility to the documents, in my way of thinking.

k

special-K 10-28-2013 08:40 AM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
I never knew of a 3.36:1 ratio in these trucks. Looks like it was just in Vans. That would be a sweet ratio to swap into a little C/10

Sandemonium 10-28-2013 10:50 AM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Thank you for posting. Great information.

indianbullet 10-28-2013 12:35 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Good stuff.

slikside 11-15-2013 09:40 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Quote:

Originally Posted by indianbullet (Post 6336671)
Good stuff.

Yes, it is. Subscribed.

Longhorn 70 11-18-2013 11:33 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
I climbed under the truck this afternoon and coudln't find the axle code on the tube. Could they have put it under the spring mount? I REALLY don't want to unbolt the springs to check it.

swamp rat 11-18-2013 11:44 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Quote:

Originally Posted by Longhorn 70 (Post 6371448)
I climbed under the truck this afternoon and coudln't find the axle code on the tube. Could they have put it under the spring mount? I REALLY don't want to unbolt the springs to check it.

Are you talking the front axle? dana 44? that axle stamp is just to the right of the front of the pumpkin towards the upper area..

LockDoc 11-19-2013 12:39 AM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
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I don't think it would be under the mount. Sometimes they are stamped pretty light. There may be some that didn't get stamped. If that is the case you would have to pull the rear cover off, check the numbers on the ring gear and use the "Red" chart in post #2...

Example: If the numbers 41 : 11 were stamped into the edge of the ring gear it would be a 3.73 ring & pinion.

LockDoc

Longhorn 70 11-19-2013 09:23 AM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Quote:

Originally Posted by swamp rat (Post 6371476)
Are you talking the front axle? dana 44? that axle stamp is just to the right of the front of the pumpkin towards the upper area..

This is for the Eaton HO52 under the Longhorn.


Thanks Leon. It may not have been stamped or these old peepers just didn't catch them. I'll look again from different angles. It may also help to get my 5 year old under there. She sees EVERYTHING.

Thanks for your guys help on this subject. I truly appreciate it.

LockDoc 11-19-2013 11:21 AM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Quote:

Originally Posted by Longhorn 70 (Post 6371915)
This is for the Eaton HO52 under the Longhorn.


Thanks Leon. It may not have been stamped or these old peepers just didn't catch them. I'll look again from different angles. It may also help to get my 5 year old under there. She sees EVERYTHING.

Thanks for your guys help on this subject. I truly appreciate it.


No problem. Be sure and take a strong light and some coarse sandpaper under with you...

Funny how those kids see it all....

LockDoc

swamp rat 11-19-2013 02:31 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
1 Attachment(s)
Quote:

Originally Posted by Longhorn 70 (Post 6371915)
This is for the Eaton HO52 under the Longhorn.

Look on top of the pumpkin passenger side of the pumpkin. I didn't think the Eaton had a stamp on the axle, i didn't see one on mine.

Longhorn 70 11-19-2013 02:44 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
OK I'll look there too. I did see some stuff stamped there.

FreeRangeChicken 11-19-2013 05:47 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Okay, here's a total noob question, please don't flame me too badly :)...

For 1967 what's a C14 and why isn't there a C10 in the chart? Quick google on 1967 and C14 yielded nonsense. Is that a misprint for C10?

JointTech 11-19-2013 06:37 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
well since i dont see it yet. I can probably OCR these are convert them to text. Ill fiddle with it today.

JointTech 11-19-2013 06:41 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Well my OCR software is kind of crappy but it wont take to much to clean this up. You guys prefer csv, xls or just a text file. the coloms are never going to line up correctly in the forum so it should be a download of some kind.

Quote:

1967
C14 . (3.73 ratio). HA-MD
C14. (3.07 ratIo). HB
C14 Positraction t3.13 ratio) HC
C14 Overdrive (4.11 ratio) HD
610..... (3.36ratlo) HI
610 (3.73 ratio) (2900 lbs.) Hi -ME
610 (4.11 ratio) (2900 lbs.) HK -MG
610 (4.11 ratio) (2400 lbs.) HL -MF
G10 Positraction (3.36 ratIo) HM-MH
GlO Positraction (3.T3 rallo) HN -MJ
610 Positractlon (4.11 ratio) (2900 lbs.) HO -MK
610 Positraction (4.11 ratIo) (2400 lbs.) HP-Ml
1(10 (3.13 rallo) HQ
PlO (4.11 rallo) HR
P10...., Posltraction (3.73 rallo) HS
PlO (3.l3ratio) HT
C20 (4.57 ratio) HU
C20 Positraction (451 ratio) HV
CZO (4.11 ratio) (Z9OU lbs.) HW
C20 (4.Slratio)DuaI Wheels HX
C20 Positraction Dual Wheels (451 ratio) HY
1(20 (45lratig) HZ-ND
P20 (4.5lratlo) IA
P20 Positraction (4.57 ratio) IB
C30 (4.57 ratIo) LW-MC-MW-MY
C30..... (5.14 ratIo) UJ -MO
C30 (Sl4ratio) IC-MR
C30 Dual Wheels (5.14 ratio). ID-MS-MV
C30 Dual Wheels (5.14 ratio) LV
C30 Positraction (5.14 rIo) lE-MO-MT
C30 Dual Wtieels, Positraction (5.14 ratio) IF -MU
P30 (5.I4ratlo) 1G
P30 Dual Wheels (5.14 ratIo) 1H
P30. . ... Posltraction 5.14 ratIo) II
C30 (4.5lratlo) iN
dO Positractlon (4.11 ratIo) JQ
C20 wP’327” (4.57 ratio) JS
C20 wr’32r, dual wheels (451 rallo) JI
C20 wP’327” (4.11 ratio) (2900 lbs.) JLJ
C30 (4.57ratio) MP
C30 (&lTrallo) MX
P20 (4.llratio) MZ
P30 (4.llratlo) NA—NB
P30 (4. ratio) NC
P30 (6.llratio) NE

LockDoc 11-19-2013 09:17 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
Quote:

Originally Posted by FreeRangeChicken (Post 6372709)
Okay, here's a total noob question, please don't flame me too badly :)...

For 1967 what's a C14 and why isn't there a C10 in the chart? Quick google on 1967 and C14 yielded nonsense. Is that a misprint for C10?


I don't see a c14 listed for '67 in any of my literature so it is probably a misprint...

LockDoc

67chevy1series 11-19-2013 10:51 PM

Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
 
For 67 is c14 3.73 positraction the equivalent to a 67 c10 with 3.73 posi?


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