72 3/4 ton rear axle...? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**RPOZ11** · 10-08-2005, 05:04 PM

What is the correct name for the axle in my truck for this year?
I found one, but the guy is asking me if I have the coarse or fine spline axles?
Can anyone discuss this for me?

**Stocker** · 10-08-2005, 05:08 PM

Dunno the particulars, but from what I've gathered on this board, mine is an Eaton HO52.

**RPOZ11** · 10-08-2005, 05:12 PM

Guy here locally wants 100.00 for it
I suppose complete would be best?
Mine currently has a 14-bolt, which I prefer, but, the shock mounts arents welded good, and it has the later shock brackets still on it.
I am unsure how much of what I have will work from my current axle to the 72 unit....

**RPOZ11** · 10-08-2005, 05:16 PM

Who is a good supplier for the parts to rebuild these Eatons?
Is there any gears made for the Eatons?

72 CustomCamper · 10-08-2005, 06:29 PM

My 72 3/4 ton has a stock Dana 60 rear in it...

Chuck

**RPOZ11** · 10-08-2005, 06:58 PM

OK, are there several different 3/4 ton axles available in 72?
Pics?

MrC1 · 10-08-2005, 07:16 PM

Mine's a Dana 60 as well.

Not sure how good this pic is, but...

Blazer1970 · 10-08-2005, 07:28 PM

Dana 60 if it looks like the picture above. If the pumpkin is round with a drop out center section and a cover on the back with ten bolts holding it on, it is an HO52 GM corporate axle. A parts store will have no idea what you are talking about if you call it an "Eaton".

Rod · 10-08-2005, 07:40 PM

17 spline on the corporate axle...thats course.

Fred T · 10-08-2005, 08:37 PM

If it were mine and the only problem with the 14-bolt was the shock mounts, I would repair or replace them. Your truck probably had the 10 bolt HO72, since it is a one ton. That would mean 4.57 gears originally, would could be upgraded to 4.10 if you can find a used set, Randy's Ring & Pinion shows to be cutting 3.90s again, but they aren't cheap. Your 14 bolt probably has 3.73 gears, could also be 4.10 or 3.42 IIRC. Far better for driving and probably why the swap was made.

**RPOZ11** · 10-08-2005, 08:44 PM

Quote:

Originally Posted by Fred T

If it were mine and the only problem with the 14-bolt was the shock mounts, I would repair or replace them. Your truck probably had the 10 bolt HO72, since it is a one ton. That would mean 4.57 gears originally, would could be upgraded to 4.10 if you can find a used set, Randy's Ring & Pinion shows to be cutting 3.90s again, but they aren't cheap. Your 14 bolt probably has 3.73 gears, could also be 4.10 or 3.42 IIRC. Far better for driving and probably why the swap was made.

Fred T.....I thank you for that input!
I was referring to my 3/4 ton CC 72 but I am certain my 1-Ton has the Eaton, with the side locking bolt.
Not sure on the 1-ton gear ratios.
Weren't there 2 different Eaton axles???
Where is Randys Ring/Pinion and do they have a website????

I am looking at R/Ring the current 14-bolt, but I am not pleased by the weld that is present on the shock mounts! Besides, I am having quite a time trying to get this axle out to begin with!

What is the Dana 60 application; I am a novice at these axles in our trucks!
I sort of am a fan of the Dana axles; is the 14-Bolt a Dana issue?

**RPOZ11** · 10-08-2005, 08:53 PM

QUESTION:

Why does one truck get 1 axle and others get different versions?
Why did GM do this?
I understand GVW! I understand a C30 from a C40, 50, 60, etc....

Just is weird to me why so many variations to the standard issue!

**Stocker** · 10-08-2005, 08:56 PM

Quote:

Originally Posted by RPOZ11

Where is Randys Ring/Pinion and do they have a website????

http://www.ring-pinion.com/

**Stocker** · 10-08-2005, 08:58 PM

Quote:

Originally Posted by RPOZ11

QUESTION: Why does one truck get 1 axle and others get different versions? Why did GM do this?

I think it may have been simply a matter of using more than one supplier...

**RPOZ11** · 10-08-2005, 08:59 PM

Was this a regional decision thru GM?
Plants on different coasts supplying the factory, or was it weight related on GVW for orders and chassis's ????

**RPOZ11** · 10-08-2005, 09:01 PM

Quote:

Originally Posted by Rod

17 spline on the corporate axle...thats course.

What is the difference between the coarse and fine spline axles units? besides the axles cuts?

**Stocker** · 10-08-2005, 09:03 PM

Quote:

Originally Posted by RPOZ11

Weren't there 2 different Eaton axles???

HO52 and HO72... been discussed before, maybe Fred or someone can fill in the details... They are very similar; I *think* differences may include axle length, and the center sections *may* be the same... also some were coil spring, some were leaf... sorry I can't be more specific, just trying to help a bit until more knowledge shows up...

**RPOZ11** · 10-08-2005, 09:07 PM

Quote:

Originally Posted by Stocker

HO52 and HO72... been discussed before, maybe Fred or someone can fill in the details... They are very similar; I *think* differences may include axle length, and the center sections *may* be the same... also some were coil spring, some were leaf... sorry I can't be more specific, just trying to help a bit until more knowledge shows up...

STOCKER.
I see you are running a 4X4...
was there an Eaton, Dana for your trucks?

**RPOZ11** · 10-08-2005, 09:13 PM

From Randy's site....
GMHO72-390 12.25" GM 3.90 R&P(HO72_'62-'72)_
LONG_PINION&_LRG_PILOT General Motors 12.25 3.90

GMHO72-411 12.25" GM 4.10 R&P(HO72_'62-'72)_
LONG_PINION&_LRG_PILOT General Motors 12.25 4.10

**RPOZ11** · 10-08-2005, 09:20 PM

Quote:

Originally Posted by Stocker

HO52 and HO72... been discussed before, maybe Fred or someone can fill in the details... They are very similar; I *think* differences may include axle length, and the center sections *may* be the same... also some were coil spring, some were leaf... sorry I can't be more specific, just trying to help a bit until more knowledge shows up...

"If the pumpkin is round with a drop out center section and a cover on the back with ten bolts holding it on, it is an HO52 GM corporate axle"

Difference between the 52 and the 72?

1967k30 · 10-08-2005, 09:31 PM

The difference between a h052 and a h072 is only the brakes.I have had 3 or 4 of both and they appear identical.There was a h110 that was optional for the c30's and factory in the c40,c50,ect.

**RPOZ11** · 10-08-2005, 09:45 PM

A commercial C/30 , and not a C/30 special order alike mine, correct???

**Stocker** · 10-08-2005, 10:29 PM

Quote:

Originally Posted by RPOZ11

STOCKER.
I see you are running a 4X4...
was there an Eaton, Dana for your trucks?

Dunno, Bud - all I can say for sure, mine is OEM on my truck, 4.10 gears, open diff... They (Eatons) have a rep for being bulletproof, but hard to get some parts for. I just don't know exactly which year/models came with which particular rear diffs. There's so much info/knowledge on this board, hopefully the right folks will chime in and answer your questions. Too bad the search feature isn't up yet, it would be a bit easier to find this stuff...

Robert1970C20rstbukt · 10-08-2005, 11:23 PM

Didn't all big block C20-30 trucks come stock with the Dana 3.54 rear? Or maybe the Eaton/Corporate rear was special ordered?

The only difference between the HO52 and HO72 rears was the size of the brakes, and the HO72 rears had the pinion load adjusting bolt, but some HO52's had the pinion load bolt too. The one on my truck has it, not sure why. The size of the HO52's brakes are 2 1/2 x 11 5/32, and the HO72's are bigger, something like 2 1/2 x 12? The H110 axle was only used in special order HD C30's and the C40 trucks. The H110 rear had 10 lug 19.5" or 20" budd rims.

roger0080 · 10-08-2005, 11:31 PM

From what I recall for 71/72 3/4 Tons is this:

Coil sprung rears got the Eaton HO52
Leaf sprung rears got the Dana 60
The 4x4's have the Eaton HO52 except for 1972 which is Dana 60 (from all the parts books that I can see)

Don't know why 2 rears for the same truck, basically.

10-08-2005, 05:04 PM	#1
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	72 3/4 ton rear axle...? What is the correct name for the axle in my truck for this year? I found one, but the guy is asking me if I have the coarse or fine spline axles? Can anyone discuss this for me? __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS

10-08-2005, 05:08 PM	#2
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,594	Dunno the particulars, but from what I've gathered on this board, mine is an Eaton HO52. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

10-08-2005, 05:12 PM	#3
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	Guy here locally wants 100.00 for it I suppose complete would be best? Mine currently has a 14-bolt, which I prefer, but, the shock mounts arents welded good, and it has the later shock brackets still on it. I am unsure how much of what I have will work from my current axle to the 72 unit.... __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS

10-08-2005, 05:16 PM	#4
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	Who is a good supplier for the parts to rebuild these Eatons? Is there any gears made for the Eatons? __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS

10-08-2005, 06:29 PM	#5
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,369	My 72 3/4 ton has a stock Dana 60 rear in it... Chuck __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

10-08-2005, 06:58 PM	#6
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	OK, are there several different 3/4 ton axles available in 72? Pics? __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS

10-08-2005, 07:16 PM	#7
MrC1 Dork For Days Join Date: Aug 2005 Location: Dallas Posts: 407	Dana 60 Mine's a Dana 60 as well. Not sure how good this pic is, but... Attached Images

10-08-2005, 07:28 PM	#8
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	Dana 60 if it looks like the picture above. If the pumpkin is round with a drop out center section and a cover on the back with ten bolts holding it on, it is an HO52 GM corporate axle. A parts store will have no idea what you are talking about if you call it an "Eaton". __________________ Tim Last edited by Blazer1970; 10-08-2005 at 07:30 PM.

10-08-2005, 07:40 PM	#9
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	17 spline on the corporate axle...thats course.

10-08-2005, 08:37 PM	#10
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	If it were mine and the only problem with the 14-bolt was the shock mounts, I would repair or replace them. Your truck probably had the 10 bolt HO72, since it is a one ton. That would mean 4.57 gears originally, would could be upgraded to 4.10 if you can find a used set, Randy's Ring & Pinion shows to be cutting 3.90s again, but they aren't cheap. Your 14 bolt probably has 3.73 gears, could also be 4.10 or 3.42 IIRC. Far better for driving and probably why the swap was made. __________________ Fred There is no such thing as too much cam...just not enough engine.

10-08-2005, 08:53 PM	#12
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	QUESTION: Why does one truck get 1 axle and others get different versions? Why did GM do this? I understand GVW! I understand a C30 from a C40, 50, 60, etc.... Just is weird to me why so many variations to the standard issue! __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS Last edited by RPOZ11; 10-08-2005 at 09:00 PM.

10-08-2005, 08:59 PM	#15
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	Was this a regional decision thru GM? Plants on different coasts supplying the factory, or was it weight related on GVW for orders and chassis's ???? __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS

10-08-2005, 09:13 PM	#19
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	From Randy's site.... GMHO72-390 12.25" GM 3.90 R&P(HO72_'62-'72)_ LONG_PINION&_LRG_PILOT General Motors 12.25 3.90 GMHO72-411 12.25" GM 4.10 R&P(HO72_'62-'72)_ LONG_PINION&_LRG_PILOT General Motors 12.25 4.10 __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS

10-08-2005, 09:31 PM	#21
1967k30 Senior Member Join Date: Sep 2005 Location: NE Posts: 363	The difference between a h052 and a h072 is only the brakes.I have had 3 or 4 of both and they appear identical.There was a h110 that was optional for the c30's and factory in the c40,c50,ect. __________________ 01 2500 Duramax,6spd,4x4,Not stock. Estimated 550rwhp/1100rwfp on fuel only. 03 3500 Duramax,6spd,4x4,Pac-Brake,not stock Estimated 500rwhp/1000rwfp fuel only 67 K10 in many pieces Little Brothers truck 67 K20 Cummins 12V/NV4500/205, D60/Eaton w/ Detroit,37" Xterrains,crossover steering, Future plans,Twins and lots of fuel.

10-08-2005, 09:45 PM	#22
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	A commercial C/30 , and not a C/30 special order alike mine, correct??? __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS



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10-08-2005, 11:23 PM	#24
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	Didn't all big block C20-30 trucks come stock with the Dana 3.54 rear? Or maybe the Eaton/Corporate rear was special ordered? The only difference between the HO52 and HO72 rears was the size of the brakes, and the HO72 rears had the pinion load adjusting bolt, but some HO52's had the pinion load bolt too. The one on my truck has it, not sure why. The size of the HO52's brakes are 2 1/2 x 11 5/32, and the HO72's are bigger, something like 2 1/2 x 12? The H110 axle was only used in special order HD C30's and the C40 trucks. The H110 rear had 10 lug 19.5" or 20" budd rims. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck Last edited by Robert1970C20rstbukt; 10-08-2005 at 11:26 PM.

10-08-2005, 11:31 PM	#25
roger0080 Registered User Join Date: Nov 2000 Location: Carver County, Minnesota, USA Posts: 626	From what I recall for 71/72 3/4 Tons is this: Coil sprung rears got the Eaton HO52 Leaf sprung rears got the Dana 60 The 4x4's have the Eaton HO52 except for 1972 which is Dana 60 (from all the parts books that I can see) Don't know why 2 rears for the same truck, basically. __________________ 72 Chev C-10 90% restored (former AZ truck) ... 71 Chev K-20 Cheyenne my vacation crusier... 72 Chev C-10 Now retired and striped after many faithful miles... 72 GMC 1500 Retired to the junk yard after bought new in '71... Last edited by roger0080; 10-09-2005 at 01:31 PM.

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