3/4 ton rear gears - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bobs409 · 04-10-2002, 12:33 PM

I just checked out the list of rear gear codes for 1971 trucks at: http://www.americanclassic.com/paint.htm?p1=axles

Did these only come with 4.10, 4.56, 4.57 and 5.14? I haven't driven my new toy (1971 C20) on the highway yet but it didn't seem like the gears where that low driving around my lot.

Where are these codes stamped anyway?

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63 Impala*66 Chevelle SS*69 Chevelle*69 C10 Stepside*71 Cheyenne 20*72 Chevelle

Parts for sale:
http://www.angelfire.com/trek/mr409/items4sale.html

da-burb · 04-10-2002, 12:49 PM

dana 60's came with 3.54 gears

Longhorn Man · 04-10-2002, 12:49 PM

Remember that the 3/4 ton and larger have tall tires, which reduces the overal gear ratio.

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

**COBALT** · 04-10-2002, 01:32 PM

I have the "HW" 4.11 gear HO52 (72?) Corp. 10 bolt axle on a '69 C20. If you have the same thing, or something similar you'll find it on the top of the differential housing on the driver's side.

It's a stamped-in code using individual letter dies that is often times very hard to read, so get a mirror, some break cleaner, a rag and a flashlight and go to work. While I was checking mine out I cleaned the entire diff. and got every code off of it.

Don't mix it up with the casting number, which is made of 7 RAISED numbers next to the deflection limitor screw. That won't help you at all.

I have a picture, but freephoto-i.net is screwed up right now and I can't get a link to the image.

Sorry.

------------------
'69 3/4 ton C20 2wd w/ 350ci/400THM and a wood bed!
'69 3/4 ton Custom 20 2wd w/ ORIGINAL 350ci/4sp Manual and a wood bed (parts beast).
Seattle, WA.

*See pics of my trucks and project at www.webshots.com!

Mike C · 04-11-2002, 07:53 PM

My big block truck has 3.54 geared Dana 60. My parts Longhorn has a 3.73 60 and my other parts truck is an unknow at this point but also a 60. The '72 sub cruises great on the highway, but it has 235 85 16 tires! Not sure on the gear.

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70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable

*Fast68Chevy* · 04-11-2002, 09:36 PM

Mike is that 60 a 3/4 ton axle ? GM lists no availability of 3.73 in any 67-72 axle until 73-up in the 14 bolt axles

3.54 is bb ratio,. 4.10 and 4.56 are dana 60 ratios

4.10 and 4.57 and 5.14 are 3/.4 ton and 1 ton ratios respectively, 5.14 is not 3/4 ton ratio, 6.17 is another 1 ton ratio but only in the H110 axle1(11,000lb axle) have yet to see one in existance though, VERY rare

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Randy- Lincoln, IL
r68c30@hotmail.com

-71 C-10 350/CH465/3.07 12 bolt 3.07/ trying to assemble! *Life and time permitting* :P
-84 Z28 Camaro 5.0L 700R4, 3.73 rear
-84 Firebird SE 2.8L. 5 speed Borg Warner
-82 Firebird 350/TH350

*parting out 5.0LTPI '81 cutlass supreme brougham, and have lots of '67-87 parts of all kinds to sell or trade*
*Paint is overrated
© RSS Enterprises 2000

[This message has been edited by Fast68Chevy (edited April 12, 2002).]

bobs409 · 04-12-2002, 06:07 AM

new69owner, since you have a pic, could you e-mail it to me? bobs409@netscape.net

I was under the truck yesterday scraping and cleaning and still haven't found it. Maybe your pic would help.

Thanks,

------------------
63 Impala*66 Chevelle SS*69 Chevelle*69 C10 Stepside*71 Cheyenne 20*72 Chevelle

Parts for sale:
http://www.angelfire.com/trek/mr409/items4sale.html

[This message has been edited by bobs409 (edited April 12, 2002).]

CE20934 · 04-12-2002, 12:14 PM

I've seen one 6.17 and that was on a '66 C30 chassis cab RV.

As for that 10-bolt Corp, that sounds like an Eaton to me. GM Corp's had ovalish covers and integral third members while the Eatons had pefectly circular covers and removable third members. Apart from its size and lack of a two-speed shifter, my rear end in my '67 C20 is a dead ringer for the Eaton 18221 under my '69 International Loadstar 1700 RV.

With 4.57s and LT235/85R16E tires, I can cruise at about 65-70 at 3000rpm. Not too shabby on the highway. Good gas mileage too.

------------------
67 C20 '78 400sb 0.030" over, 9:1 cr, CC Xtreme 4x4 254H, port-matched '69 882 heads & stock cast iron intake, rebuilt Q-jet, Summit headers (1 5/8" primaries), true dual 2 1/2" glasspacked exhaust, NP435CR trans, 4.57 Eaton rear end.
It's a decent-looking work truck. No top-end, but it's great off the line.

*Fast68Chevy* · 04-12-2002, 12:20 PM

eaton and corp are one in the same, lol

eaton/chevy/corp 3/4 ton and 1 ton axles are perfectly round salad bowl cover with 10 bolts and yes has the removeable banjo type carrier just like a ford 9"

corp= chevy
corp also= for or dodge

corp means manufacturer's own component

a ford 9", chrysler 8 3/4", chevrolet 14 bolt SF 10.5", 14 bolt 9.5" SF, and chevrolet 12 bolt are both a corp axle, and so forth

dana is not a corp when used under other than dana vehicles,
and since dana never built complete vehicles, there are no coirp dana axle, they did build and do build truck frames however

CE20934(2wd 3/4 ton V8 127" wheelbase fleetside bed), 6.17 axle was the axle with 10 wheel studs and transmission tail/driveshaft mounted parking drum brake.
That is what you saw, correct ?
very cool

pics ? that truck stil around ? would be neato..

------------------
------------------
Randy- Lincoln, IL
r68c30@hotmail.com

-71 C-10 350/CH465/3.07 12 bolt 3.07/ trying to assemble! *Life and time permitting* :P
-84 Z28 Camaro 5.0L 700R4, 3.73 rear
-84 Firebird SE 2.8L. 5 speed Borg Warner
-82 Firebird 350/TH350

*parting out 5.0LTPI '81 cutlass supreme brougham, and have lots of '67-87 parts of all kinds to sell or trade*
*Paint is overrated
© RSS Enterprises 2000

[This message has been edited by Fast68Chevy (edited April 12, 2002).]

Mike C · 04-12-2002, 05:04 PM

Yes Randy, It is a Dana 60. I pulled the cover and it is definitely 3.73, but like any old truck, who knows what has been changed in it's 30+ years. I don't always trust what GM said was available and what was REALLY available. I have found too many anomalies in the past, especially with rear axle coding.

------------------
70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable

williso · 04-13-2002, 07:36 AM

If anyone is interested, I have Dana-Spicer's own manual for 1967-78 which lists the Dana 60 rears that they provided for GM. For C20 trucks during the 67-72 period the ratios available were:
3.54 for leaf spring rears, 1968-72
3.54 for coil spring rears, 1968-72
3.73 for leaf spring rears, 1968-70
3.73 for coil spring rears, 1969-71
4.10 for leaf spring rears, 1968-72
4.10 for coil spring rears, 1969-72
4.56 for leaf spring rears, 1968-72
4.56 for coil spring rears, 1969-72

I'd be happy to scan in and email the relevant pages (8) from the manual to someone would be willing to post them on the board for reference.

Rod · 04-13-2002, 08:57 AM

I myself have only seen two 1 tons that had the 6:17 ratio... they were a 1971 and a 1972. Very odd looking diff.... looks like very large dana cover. Ten bolt studs for the wheels. The have two vacuum pods underneath the cab of the truck to assist in braking. Both had a drum style parking brake on the rear on the tranny also. I have seen a 1972 1/2 ton with that parking brake type option also. Rod

------------------
Senior active member of the best truck message board on the net.
71 1/2 ton Suburban 4x4, 350/350
72 1ton tow truck 402BB w/Holmes 440 wrecker / on propane
85 FXSB Harley Lowrider
72 Triumph 650 Bonneville 5spd

04-10-2002, 12:33 PM	#1
bobs409 1969 Custom 30 wrecker Join Date: Sep 2001 Location: Pottsville, Pa Posts: 2,611	3/4 ton rear gears I just checked out the list of rear gear codes for 1971 trucks at: http://www.americanclassic.com/paint.htm?p1=axles Did these only come with 4.10, 4.56, 4.57 and 5.14? I haven't driven my new toy (1971 C20) on the highway yet but it didn't seem like the gears where that low driving around my lot. Where are these codes stamped anyway? ------------------ 63 Impala66 Chevelle SS69 Chevelle69 C10 Stepside71 Cheyenne 20*72 Chevelle Parts for sale: http://www.angelfire.com/trek/mr409/items4sale.html __________________ Bob 63 Impala 283/PG/3.36 (under restoration) 66 Impala 327/PG/3.36 66 Chevelle SS 409/M22/3.55 69 Chevelle 307/PG/3.08 (future restoration) 69 C10 short stepside 454/TH350/3.73 69 Custom 30 tow truck 350/4 spd/4.10 (resto done, CRUISIN TIME!) 71 Cheyenne 20 fleetside 350/4 spd/4.10 71 Chevelle 6/PG/3.08 72 Chevelle 454/M21/4.10

04-10-2002, 12:49 PM	#2
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	dana 60's came with 3.54 gears __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

04-10-2002, 01:32 PM	#4
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	I have the "HW" 4.11 gear HO52 (72?) Corp. 10 bolt axle on a '69 C20. If you have the same thing, or something similar you'll find it on the top of the differential housing on the driver's side. It's a stamped-in code using individual letter dies that is often times very hard to read, so get a mirror, some break cleaner, a rag and a flashlight and go to work. While I was checking mine out I cleaned the entire diff. and got every code off of it. Don't mix it up with the casting number, which is made of 7 RAISED numbers next to the deflection limitor screw. That won't help you at all. I have a picture, but freephoto-i.net is screwed up right now and I can't get a link to the image. Sorry. ------------------ '69 3/4 ton C20 2wd w/ 350ci/400THM and a wood bed! '69 3/4 ton Custom 20 2wd w/ ORIGINAL 350ci/4sp Manual and a wood bed (parts beast). Seattle, WA. *See pics of my trucks and project at www.webshots.com! __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

04-11-2002, 07:53 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,713	My big block truck has 3.54 geared Dana 60. My parts Longhorn has a 3.73 60 and my other parts truck is an unknow at this point but also a 60. The '72 sub cruises great on the highway, but it has 235 85 16 tires! Not sure on the gear. ------------------ 70 GMC 3/4 ton Sierra Grande 402/TH400 72 Jimmy 4WD 4spd 4" & 35's 64 Corvette Coupe 68 Camaro 'vert TPI & TH700 69 Z/28 355 12.6's @110 72 Datsun 240Z-ol' reliable __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

04-12-2002, 06:07 AM	#7
bobs409 1969 Custom 30 wrecker Join Date: Sep 2001 Location: Pottsville, Pa Posts: 2,611	new69owner, since you have a pic, could you e-mail it to me? bobs409@netscape.net I was under the truck yesterday scraping and cleaning and still haven't found it. Maybe your pic would help. Thanks, ------------------ 63 Impala66 Chevelle SS69 Chevelle69 C10 Stepside71 Cheyenne 20*72 Chevelle Parts for sale: http://www.angelfire.com/trek/mr409/items4sale.html [This message has been edited by bobs409 (edited April 12, 2002).] __________________ Bob 63 Impala 283/PG/3.36 (under restoration) 66 Impala 327/PG/3.36 66 Chevelle SS 409/M22/3.55 69 Chevelle 307/PG/3.08 (future restoration) 69 C10 short stepside 454/TH350/3.73 69 Custom 30 tow truck 350/4 spd/4.10 (resto done, CRUISIN TIME!) 71 Cheyenne 20 fleetside 350/4 spd/4.10 71 Chevelle 6/PG/3.08 72 Chevelle 454/M21/4.10

04-10-2002, 12:49 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Remember that the 3/4 ton and larger have tall tires, which reduces the overal gear ratio. ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite. If you need a pic posted, E-mail me at longhornmail@yahoo.com Andy, in Columbus Ohio

04-11-2002, 09:36 PM	#6
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	Mike is that 60 a 3/4 ton axle ? GM lists no availability of 3.73 in any 67-72 axle until 73-up in the 14 bolt axles 3.54 is bb ratio,. 4.10 and 4.56 are dana 60 ratios 4.10 and 4.57 and 5.14 are 3/.4 ton and 1 ton ratios respectively, 5.14 is not 3/4 ton ratio, 6.17 is another 1 ton ratio but only in the H110 axle1(11,000lb axle) have yet to see one in existance though, VERY rare ------------------ Randy- Lincoln, IL r68c30@hotmail.com -71 C-10 350/CH465/3.07 12 bolt 3.07/ trying to assemble! Life and time permitting :P -84 Z28 Camaro 5.0L 700R4, 3.73 rear -84 Firebird SE 2.8L. 5 speed Borg Warner -82 Firebird 350/TH350 parting out 5.0LTPI '81 cutlass supreme brougham, and have lots of '67-87 parts of all kinds to sell or trade *Paint is overrated © RSS Enterprises 2000 [This message has been edited by Fast68Chevy (edited April 12, 2002).]

04-12-2002, 12:14 PM	#8
CE20934 Senior Member Join Date: Apr 2002 Location: Help! I'm in an office park with its own network of freeways! Posts: 470	I've seen one 6.17 and that was on a '66 C30 chassis cab RV. As for that 10-bolt Corp, that sounds like an Eaton to me. GM Corp's had ovalish covers and integral third members while the Eatons had pefectly circular covers and removable third members. Apart from its size and lack of a two-speed shifter, my rear end in my '67 C20 is a dead ringer for the Eaton 18221 under my '69 International Loadstar 1700 RV. With 4.57s and LT235/85R16E tires, I can cruise at about 65-70 at 3000rpm. Not too shabby on the highway. Good gas mileage too. ------------------ 67 C20 '78 400sb 0.030" over, 9:1 cr, CC Xtreme 4x4 254H, port-matched '69 882 heads & stock cast iron intake, rebuilt Q-jet, Summit headers (1 5/8" primaries), true dual 2 1/2" glasspacked exhaust, NP435CR trans, 4.57 Eaton rear end. It's a decent-looking work truck. No top-end, but it's great off the line. __________________ '67 C20--427 tall deck/SM420, 4.10 HO52 (Michigan has not been kind to the Old Man) '95 Caprice--355 LT1/T56/3.42 8.5" 10-bolt (daily driver, almost 300k on the chassis) '07 Outback--wife's car. 125k & counting. No head gasket or transmission issues yet. fingers crossed

04-12-2002, 12:20 PM	#9
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	eaton and corp are one in the same, lol eaton/chevy/corp 3/4 ton and 1 ton axles are perfectly round salad bowl cover with 10 bolts and yes has the removeable banjo type carrier just like a ford 9" corp= chevy corp also= for or dodge corp means manufacturer's own component a ford 9", chrysler 8 3/4", chevrolet 14 bolt SF 10.5", 14 bolt 9.5" SF, and chevrolet 12 bolt are both a corp axle, and so forth dana is not a corp when used under other than dana vehicles, and since dana never built complete vehicles, there are no coirp dana axle, they did build and do build truck frames however CE20934(2wd 3/4 ton V8 127" wheelbase fleetside bed), 6.17 axle was the axle with 10 wheel studs and transmission tail/driveshaft mounted parking drum brake. That is what you saw, correct ? very cool pics ? that truck stil around ? would be neato.. ------------------ ------------------ Randy- Lincoln, IL r68c30@hotmail.com -71 C-10 350/CH465/3.07 12 bolt 3.07/ trying to assemble! Life and time permitting :P -84 Z28 Camaro 5.0L 700R4, 3.73 rear -84 Firebird SE 2.8L. 5 speed Borg Warner -82 Firebird 350/TH350 parting out 5.0LTPI '81 cutlass supreme brougham, and have lots of '67-87 parts of all kinds to sell or trade *Paint is overrated © RSS Enterprises 2000 [This message has been edited by Fast68Chevy (edited April 12, 2002).]

04-12-2002, 05:04 PM	#10
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,713	Yes Randy, It is a Dana 60. I pulled the cover and it is definitely 3.73, but like any old truck, who knows what has been changed in it's 30+ years. I don't always trust what GM said was available and what was REALLY available. I have found too many anomalies in the past, especially with rear axle coding. ------------------ 70 GMC 3/4 ton Sierra Grande 402/TH400 72 Jimmy 4WD 4spd 4" & 35's 64 Corvette Coupe 68 Camaro 'vert TPI & TH700 69 Z/28 355 12.6's @110 72 Datsun 240Z-ol' reliable __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

04-13-2002, 07:36 AM	#11
williso Registered User Join Date: Jan 2000 Location: Manheim PA USA Posts: 80	If anyone is interested, I have Dana-Spicer's own manual for 1967-78 which lists the Dana 60 rears that they provided for GM. For C20 trucks during the 67-72 period the ratios available were: 3.54 for leaf spring rears, 1968-72 3.54 for coil spring rears, 1968-72 3.73 for leaf spring rears, 1968-70 3.73 for coil spring rears, 1969-71 4.10 for leaf spring rears, 1968-72 4.10 for coil spring rears, 1969-72 4.56 for leaf spring rears, 1968-72 4.56 for coil spring rears, 1969-72 I'd be happy to scan in and email the relevant pages (8) from the manual to someone would be willing to post them on the board for reference.

04-13-2002, 08:57 AM	#12
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	I myself have only seen two 1 tons that had the 6:17 ratio... they were a 1971 and a 1972. Very odd looking diff.... looks like very large dana cover. Ten bolt studs for the wheels. The have two vacuum pods underneath the cab of the truck to assist in braking. Both had a drum style parking brake on the rear on the tranny also. I have seen a 1972 1/2 ton with that parking brake type option also. Rod ------------------ Senior active member of the best truck message board on the net. 71 1/2 ton Suburban 4x4, 350/350 72 1ton tow truck 402BB w/Holmes 440 wrecker / on propane 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.



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