Help ID Diff... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

elks · 06-13-2011, 12:59 AM

1970 Chevy PU long bed. I think a 3/4 ton. supposedly a stock diff. It has a large round rear cover with 10 bolts, but seemed way heavier duty than a 10 bolt. Had drum brakes, but the contact surface was pretty thin left to right. The fron of the diif and rear both unbolted to access pumpkin.

I have pics on my phone, but no way to get to computer. It so had 456 gears.

TrkEnvy · 06-13-2011, 02:04 AM

Its either a eaton HO52 if its a C20 or a HO72 if its a C30. If you dont mind the low gear its not a bad rear. But if you want fuel econ then your gonna have to ditch it. They never made a gear taller than 4.10 for it.

elks · 06-13-2011, 11:10 PM

Quote:

Originally Posted by TrkEnvy

Its either a eaton HO52 if its a C20 or a HO72 if its a C30. If you dont mind the low gear its not a bad rear. But if you want fuel econ then your gonna have to ditch it. They never made a gear taller than 4.10 for it.

It looked really strong. How good of an axle is it? I am not sure if I want it, but I am looking for a strong set of 1 ton axles for my blazer. SOme research shows a 14 bolt detroit locker will fit it.

TrkEnvy · 06-14-2011, 01:05 AM

I wasnt aware that a 14 bolt carrier would fit it. Makes me a bit skeptical, but my dad has one in his '66 C20 and he is ditching it for a 14 bolt. They can be picked up for a song in junkyards cuz GM made so many and parts are cheap for em. In my opinion the Eaton rears arent bad, but its old tech. GM used them from '47-'72 so its definately dated.

Longhorn Man · 06-14-2011, 09:23 AM

your worn drums are not avalible.... except from junk yards and places like this site that parts out old trucks.
If it is a 3/4 ton (coil springs maybe?) then it is an HO52, the HO72 (dam near the exact same thing) was only under c/30 trucks.
it is a tough rock solid rear. but parts are getting hard to find.

ChevLoRay · 06-14-2011, 01:40 PM

Somewhere on the top of the axle housing, usually the right side, there will be a series of letters/numbers stamped on that tube. If you can read those, there's a way to decipher specifically what it is, ratio, etc., and I think you can also narrow the year down to one or two, in the translation.

bosco200 · 06-14-2011, 07:42 PM

You got a HO-52 my friend...I got the same rear end in my C20 with 4.57's....The rear end is a HOSS....if you want a good rear end Id stick with it ....but yes if you keep the 4.57's in the gas mileage will not be the best...I get around 8...and im pushing around 4,000 RPM at 55 mph.

gmebey · 06-14-2011, 10:47 PM

Look at the front of rear end, if it has a bolt/lock nut on the driver side it is a H072.

They made some C20 with 1-ton rear ends, which I think they called "supper"....correct me I'm wrong here.

06-13-2011, 12:59 AM	#1
elks Registered User Join Date: Mar 2009 Location: NW, Colorado Posts: 285	Help ID Diff... 1970 Chevy PU long bed. I think a 3/4 ton. supposedly a stock diff. It has a large round rear cover with 10 bolts, but seemed way heavier duty than a 10 bolt. Had drum brakes, but the contact surface was pretty thin left to right. The fron of the diif and rear both unbolted to access pumpkin. I have pics on my phone, but no way to get to computer. It so had 456 gears. __________________ Confidence is the feeling we have before we fully comprehend the situation

06-13-2011, 02:04 AM	#2
TrkEnvy Registered User Join Date: Apr 2011 Location: Las Vegas, NV Posts: 264	Re: Help ID Diff... Its either a eaton HO52 if its a C20 or a HO72 if its a C30. If you dont mind the low gear its not a bad rear. But if you want fuel econ then your gonna have to ditch it. They never made a gear taller than 4.10 for it.

06-14-2011, 01:05 AM	#4
TrkEnvy Registered User Join Date: Apr 2011 Location: Las Vegas, NV Posts: 264	Re: Help ID Diff... I wasnt aware that a 14 bolt carrier would fit it. Makes me a bit skeptical, but my dad has one in his '66 C20 and he is ditching it for a 14 bolt. They can be picked up for a song in junkyards cuz GM made so many and parts are cheap for em. In my opinion the Eaton rears arent bad, but its old tech. GM used them from '47-'72 so its definately dated.

06-14-2011, 09:23 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Help ID Diff... your worn drums are not avalible.... except from junk yards and places like this site that parts out old trucks. If it is a 3/4 ton (coil springs maybe?) then it is an HO52, the HO72 (dam near the exact same thing) was only under c/30 trucks. it is a tough rock solid rear. but parts are getting hard to find.

06-14-2011, 01:40 PM	#6
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: Help ID Diff... Somewhere on the top of the axle housing, usually the right side, there will be a series of letters/numbers stamped on that tube. If you can read those, there's a way to decipher specifically what it is, ratio, etc., and I think you can also narrow the year down to one or two, in the translation. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

06-14-2011, 07:42 PM	#7
bosco200 Registered User Join Date: Dec 2009 Location: Ste. Genevieve, MO Posts: 526	Re: Help ID Diff... You got a HO-52 my friend...I got the same rear end in my C20 with 4.57's....The rear end is a HOSS....if you want a good rear end Id stick with it ....but yes if you keep the 4.57's in the gas mileage will not be the best...I get around 8...and im pushing around 4,000 RPM at 55 mph. Attached Images

06-14-2011, 10:47 PM	#8
gmebey Registered User Join Date: May 2011 Location: Fort Collins, Colorado Posts: 95	Re: Help ID Diff... Look at the front of rear end, if it has a bolt/lock nut on the driver side it is a H072. They made some C20 with 1-ton rear ends, which I think they called "supper"....correct me I'm wrong here.



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