Eaton/Rockwell rear end ID?'s - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Backroads · 08-22-2005, 11:02 PM

I recently purchased a 71 Chev C20 LB 2wd w/sm465. I have purchased all apearently available literature for this truck but am unable to find any info in them on ID as well as repair/parts info on the equipped axle. I also couldn't find anything in the manuals on the sm465 four speed, but I did find info for it in some of the off road sites, particularly Novak's.

I believe the axle is an Eaton or Rockwell product, it has eight lugs and the axles are floaters, but I can find no numbers on it. A rather large axle for a 3/4 ton in my opinion. The center section has a pot cover on the back, and the center section in front is also removable. I have been to several off road sites looking for info on this rear and most just skim over it with no real info or way of ID'ing the axle.

Any way of positively ID'ing this axle?
Any source for info on these oddball rears?
Does this axle, or were any equipped with limited slips?
Can they be retrofitted with a limited slip?

Thanks in advance for any help.
Marty

**Yukon Jack** · 08-23-2005, 09:50 AM

That axle is definitely an Eaton axle. It should be the HO52. I do not know if a limited slip was available but a bunch had factory Detroit Lockers. They were called No-Spins.

You can put a 14 bolt's Detroit Locker with 14 bolt axles in the Eaton axle. I don't know if you can retrofit a limited slip.

The SM465 has the following gear ratio:

1st 6.55, 2nd 3.58, 3rd 1.70, 4th direct. Revearse is 6.09. It has PTO openings on both sides and it takes 8 pints of gear oil.

**JIMs70GMC** · 08-23-2005, 10:16 AM

Only the no-spin available, used. Axle was in service from 47-72 so not too odd ball. only factory gears- 4.10, 4.56 and 5.13. Has split case carrier like 14 bolt. Have pics in link in signature. H052 was 3/4 ton w/ 12" brakes, H072 was in 1 ton and had 13" brakes. Per my 1970 chassis manual weight capacity was limited by chassis/brakes/springs, axle never changed and was found under 14000lb GVWR vehicles(from my 72 C30 wrecker label plate). My 71 K20 is GVWR at 7500lbs.

**JIMs70GMC** · 08-23-2005, 10:19 AM

Here's the carrier w/ detroit:

masterbeavis · 08-23-2005, 09:09 PM

eatons have a really coarse R&P. I seen mine and was like YIKES!!

Backroads · 08-23-2005, 09:58 PM

A wealth of info and I thank each and every one of you.

I think it has 4:10's based on the engine rpm and tire size. About 3200 @ 70mph.

Has anyone ever broken one of these rears? What about brake jobs, are parts readily available? My reason for asking all these questions, is this is going to be my daily driver and will see some towing work when I pull my travel trailer.

I haven't had the time to get it off the ground to even check if it has a posi. I intend to do that tomorrow. Posi is nice when I get the TT off road and would be a welcome addition.

**JIMs70GMC** · 08-24-2005, 05:41 AM

What will do these rear ends in fast is no oil. All the bolts holding the cover and center section on are through holes into the case and potential spots for leaking. Other than that I've never heard of one breaking. If you have driven the truck, you'll no if it has a no-spin, as it will tend to chirp the tires through corners or during slow speed sharp turns. When you straighten back out you'll hear the no-spin "ratchet" or un-lock.
I've replaced my wheel cyclinders w/ off the shelf parts. As with anything old it's always best to take the part with you when you go to the parts store.

**Yukon Jack** · 08-24-2005, 09:47 AM

You can convert to disk brakes on that rear axle. A member works at Blackbird Customs and they sell the brackets.

Dean · 08-24-2005, 10:19 AM

Very tough rearend. I've got lockers in all of mine plus I've picked up a few extras over the years. Don't forget to look at the trucks older than ours also. I've found a couple that way. Even found one in a yard's 66 boom truck once.

I was running a car at the Goodguys race in Columbus a few years ago and was looking the Hemi Under Glass car. I kept thinking that rearend looked familiar. I asked the owner and he said it was the Eaton out of our trucks. Only thing he could find to hold up. He ran the non locker version with steering brakes. He said he used to run a Dana but it kept exploding.

I agree with Jim on lack of oil would be only problem. I've had problems at times getting the back cover to completely stop leaking. I've been able to purchase every part new. Rebuilt or replaced every piece on my blue and the green K20s.

Backroads · 08-24-2005, 05:33 PM

Thanks again guys. I think I will stay with this rear but may opt to go with the 14b detroit locker and axles if this rear isn't posi(locking). How about the 14b drum backing plates, do they fit or can be modified to fit the eaton axle housing?

08-22-2005, 11:02 PM	#1
Backroads Registered User Join Date: Aug 2005 Location: Baltimore Maryalnd USA Posts: 11	Eaton/Rockwell rear end ID?'s I recently purchased a 71 Chev C20 LB 2wd w/sm465. I have purchased all apearently available literature for this truck but am unable to find any info in them on ID as well as repair/parts info on the equipped axle. I also couldn't find anything in the manuals on the sm465 four speed, but I did find info for it in some of the off road sites, particularly Novak's. I believe the axle is an Eaton or Rockwell product, it has eight lugs and the axles are floaters, but I can find no numbers on it. A rather large axle for a 3/4 ton in my opinion. The center section has a pot cover on the back, and the center section in front is also removable. I have been to several off road sites looking for info on this rear and most just skim over it with no real info or way of ID'ing the axle. Any way of positively ID'ing this axle? Any source for info on these oddball rears? Does this axle, or were any equipped with limited slips? Can they be retrofitted with a limited slip? Thanks in advance for any help. Marty

08-23-2005, 09:50 AM	#2
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,686	That axle is definitely an Eaton axle. It should be the HO52. I do not know if a limited slip was available but a bunch had factory Detroit Lockers. They were called No-Spins. You can put a 14 bolt's Detroit Locker with 14 bolt axles in the Eaton axle. I don't know if you can retrofit a limited slip. The SM465 has the following gear ratio: 1st 6.55, 2nd 3.58, 3rd 1.70, 4th direct. Revearse is 6.09. It has PTO openings on both sides and it takes 8 pints of gear oil. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

08-23-2005, 10:16 AM	#3
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Only the no-spin available, used. Axle was in service from 47-72 so not too odd ball. only factory gears- 4.10, 4.56 and 5.13. Has split case carrier like 14 bolt. Have pics in link in signature. H052 was 3/4 ton w/ 12" brakes, H072 was in 1 ton and had 13" brakes. Per my 1970 chassis manual weight capacity was limited by chassis/brakes/springs, axle never changed and was found under 14000lb GVWR vehicles(from my 72 C30 wrecker label plate). My 71 K20 is GVWR at 7500lbs. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

08-23-2005, 10:19 AM	#4
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Here's the carrier w/ detroit: __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

08-23-2005, 09:09 PM	#5
masterbeavis Having issues Join Date: Jul 2005 Location: Eldorado Ca, an hour east of sacramento Posts: 696	eatons have a really coarse R&P. I seen mine and was like YIKES!! __________________ Quando Omni Flunkus Moritati. The Man's Prayer: "I'm a man, but I can change, if I have to, I guess."

08-23-2005, 09:58 PM	#6
Backroads Registered User Join Date: Aug 2005 Location: Baltimore Maryalnd USA Posts: 11	Thanks for all the info guys. 2 more ?'s A wealth of info and I thank each and every one of you. I think it has 4:10's based on the engine rpm and tire size. About 3200 @ 70mph. Has anyone ever broken one of these rears? What about brake jobs, are parts readily available? My reason for asking all these questions, is this is going to be my daily driver and will see some towing work when I pull my travel trailer. I haven't had the time to get it off the ground to even check if it has a posi. I intend to do that tomorrow. Posi is nice when I get the TT off road and would be a welcome addition.

08-24-2005, 05:41 AM	#7
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	What will do these rear ends in fast is no oil. All the bolts holding the cover and center section on are through holes into the case and potential spots for leaking. Other than that I've never heard of one breaking. If you have driven the truck, you'll no if it has a no-spin, as it will tend to chirp the tires through corners or during slow speed sharp turns. When you straighten back out you'll hear the no-spin "ratchet" or un-lock. I've replaced my wheel cyclinders w/ off the shelf parts. As with anything old it's always best to take the part with you when you go to the parts store. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm Last edited by JIMs70GMC; 08-24-2005 at 05:42 AM.

08-24-2005, 09:47 AM	#8
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,686	You can convert to disk brakes on that rear axle. A member works at Blackbird Customs and they sell the brackets. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

08-24-2005, 10:19 AM	#9
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	Very tough rearend. I've got lockers in all of mine plus I've picked up a few extras over the years. Don't forget to look at the trucks older than ours also. I've found a couple that way. Even found one in a yard's 66 boom truck once. I was running a car at the Goodguys race in Columbus a few years ago and was looking the Hemi Under Glass car. I kept thinking that rearend looked familiar. I asked the owner and he said it was the Eaton out of our trucks. Only thing he could find to hold up. He ran the non locker version with steering brakes. He said he used to run a Dana but it kept exploding. I agree with Jim on lack of oil would be only problem. I've had problems at times getting the back cover to completely stop leaking. I've been able to purchase every part new. Rebuilt or replaced every piece on my blue and the green K20s. Attached Images

08-24-2005, 05:33 PM	#10
Backroads Registered User Join Date: Aug 2005 Location: Baltimore Maryalnd USA Posts: 11	One more please? Thanks again guys. I think I will stay with this rear but may opt to go with the 14b detroit locker and axles if this rear isn't posi(locking). How about the 14b drum backing plates, do they fit or can be modified to fit the eaton axle housing?



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