Help identify a 3/4 ton rearend - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Yellow Cheyenne · 09-30-2002, 12:18 AM

I am parting a '72 Chevy Longhorn 3/4 ton pickup that has what I believe is a non original rear end. The rear axle has 1/2" studs that are smaller than what the front discs have (9/16" I think). The rear housing also has some paint left on it as opposed to the rest of the under carriage.

Both the front and rear of the center section can be removed. The rear cover has 10 bolts in it and is basically smooth. The front is cast iron and I believe it also has 10 bolts holding it in. It is a full floater set up. The pinion input can be unbolted from the rest of the front cast iron piece. The only numbers I could find on it are on the front left side of the cast iron piece and the numbers are 3834635. Can anyone help identify this piece? Thanks in advance.

chevynut · 09-30-2002, 12:36 AM

If you could post a pic of the rear pumpkin it should be easier to identify.

mikep · 09-30-2002, 12:52 AM

Sounds like an eaton .

Blue_71 · 09-30-2002, 02:24 AM

sounds like eaton to me too, my 71 3/4 ton 4x4 one has 9/16 threads though

ckhd · 09-30-2002, 10:51 AM

Yeah, it's the "Eaton" or H-072/H-052 (same thing, different names). My '68 H-072 has 1/2" studs.

mikep · 09-30-2002, 11:15 AM

I know where one is around the Seattle area in a boneyard with the "maximum traction" option if anyone wants it. ala detroit locker . Its under a 67 and has 4.10 gears

crew70 · 09-30-2002, 11:41 AM

remember now the only diference between a ho52 and ho72 is the ho72 has 13in brake drums and only came on daullys.

ckhd · 09-30-2002, 01:19 PM

I thought it was the H-110 that came on duallies...

jku72 · 09-30-2002, 01:45 PM

I have an HO 72 under single rear wheels. But I do think the only difference is in the brake size.

**COBALT** · 09-30-2002, 02:38 PM

Does it look like this?:

crew70 · 09-30-2002, 04:47 PM

yep,ho52.

Rod · 09-30-2002, 09:51 PM

There was an 11000 lbs gvw rear end that came on 1 ton duallies also... but it has ten studs on the drums. Still the truck was rated as 14000 lbs total.
My dually has the 7500 lbs rear with the aux spring kit that made it a factory 11000lbs rear also but is 8 bolt stud pattern. 9/16 studs in 70 up I believe maybe just 71-72.

The 11000 pound factory rear had vacyuum assist brake pods that mounted under the cab.... once you see one you will always remember the difference. Sorry no pic.

mikep · 09-30-2002, 09:59 PM

OK...Why does my 7500 GVW 68 3/4 ton C20 with heavy duty coils, 4speed , and originally a factory big block have a dana 60 while all the other similarly equipped trucks I have seen have Eatons? Was there any formula to determine which trucks would have what rear ends?

Longhorn Man · 09-30-2002, 11:49 PM

If not mistaken, Danas were just another option that should have been opted for a more trucks than they were.

mikep · 10-01-2002, 12:15 AM

I just checked my option sheet. I got it along with the protectoplate, '68 service manual and warranty book. Not bad for $500. Other than HD rear springs and 396 engine there is nothing concerning the driveline. I did see a 67 in the boneyard the other day. I go once or twice a week . I've been a junkyard junky since I was 12. It had a eaton with a detroit locker and was optioned as such on the build sheet behind the rear seat as "extreme traction" or something like that. I check those . I am a dork . I'm thinking the Eaton was the option and the dana was the standard rear end under 3/4 tons. It might have been what they later called the heavy 3/4 ton option.

Longhorn Man · 10-01-2002, 12:18 AM

Dana was not standard.
Many things never made it to the option sheet. For example, the leaf/coil spring debate. I have never seen (in person) an option sheet that states one or the other, yet my GMC has coils in back, and I have seen a few leaf spring 1/2 ton chevys...
Lots of mysteries.

mikep · 10-01-2002, 12:51 AM

Thats right. The build sheet had it listed as "Maximum Traction"

Sounds rather ominous doesnt it?

Yellow Cheyenne · 10-01-2002, 09:18 AM

Cobalt. Mine does look like that, except mine is a leaf spring set up. I will check for posi and ratio and let everyone know. Thanks to everyone for helping me out.

**COBALT** · 10-01-2002, 01:42 PM

Well, I may catch heat for what I'm about to say, but it won't be the first time on this topic. longhornmail hit on it in his previous post. There's some large patches of grey area when it comes to the rear suspension/differential debate. It is NOT as standardized as people might think. The numbers on the differential you see in the picture above match to an HO72. Now before everyone jumps on me I checked this out, and technically you guys are correct about the configuration issues of leaf vs. coil sprung suspensions and 5200, 7200, and 11000 axles with or without the HD spring and/or overload spring options. All that aside the differential codes are what they are. Mine does not match the numbers for an HO52.

Another thing. I think I mentioned in another post that these axles aren't technically "Eaton" axles. This is a source of confusion for a lot of people. Eaton made the carriers, and the optional posi units and such, but they didn't produce the whole axle.

crew70 · 10-01-2002, 07:38 PM

ok i am going off of what I have learned from you guys on the board.
anway can you tell from my code what it is?

3934635

**COBALT** · 10-01-2002, 07:42 PM

That's the casting number of the housing. Look in these areas for all of the codes. Like an engine you have to use them all to figure out what you have, and then there's a website that can tell you (don't remember the URL-sorry):

crew70 · 10-01-2002, 08:05 PM

ok heres what I found
tpw1222g
3843067
3934635

couldn t find any numbers on the yoke like it says in your pic.

Yellow Cheyenne · 10-02-2002, 01:43 AM

I opened mine up tonight. It is 4.10 non posi/non locker. It is in good shape if any one wants it. Otherwise it will go to junkyard this weekend.

**COBALT** · 10-03-2002, 11:59 AM

crew70: check inside the yoke. There should be a huge-a$$ nut inside that should have some codes stamped into it...

We went to all this trouble for a junked differential? Oh well it's good info.

Yellow Cheyenne · 10-03-2002, 12:42 PM

It's only junk of nobody wants it.

09-30-2002, 12:18 AM	#1
Yellow Cheyenne Registered User Join Date: Jun 2001 Location: Eastern Kansas Posts: 488	Help identify a 3/4 ton rearend I am parting a '72 Chevy Longhorn 3/4 ton pickup that has what I believe is a non original rear end. The rear axle has 1/2" studs that are smaller than what the front discs have (9/16" I think). The rear housing also has some paint left on it as opposed to the rest of the under carriage. Both the front and rear of the center section can be removed. The rear cover has 10 bolts in it and is basically smooth. The front is cast iron and I believe it also has 10 bolts holding it in. It is a full floater set up. The pinion input can be unbolted from the rest of the front cast iron piece. The only numbers I could find on it are on the front left side of the cast iron piece and the numbers are 3834635. Can anyone help identify this piece? Thanks in advance. __________________ '72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72) '56 Chevy short step V-8 (My dad bought it new!!) '70 Olds 442 convertible '70 Olds Rallye 350

09-30-2002, 12:36 AM	#2
chevynut Registered User Join Date: Sep 2000 Location: Tampa, FL. USA Posts: 171	If you could post a pic of the rear pumpkin it should be easier to identify. __________________ Mike 1989 C1500 SWB Reg Cab 2003 Chevy Tahoe Z-71 70 Camaro RS/SS - 454

09-30-2002, 12:52 AM	#3
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Sounds like an eaton . __________________ No truck :-(

09-30-2002, 10:51 AM	#5
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	Yeah, it's the "Eaton" or H-072/H-052 (same thing, different names). My '68 H-072 has 1/2" studs. __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?

09-30-2002, 11:15 AM	#6
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	I know where one is around the Seattle area in a boneyard with the "maximum traction" option if anyone wants it. ala detroit locker . Its under a 67 and has 4.10 gears __________________ No truck :-(

09-30-2002, 11:41 AM	#7
crew70 Registered User Join Date: Jan 2002 Location: shafer,mn,usa Posts: 316	remember now the only diference between a ho52 and ho72 is the ho72 has 13in brake drums and only came on daullys. __________________ 70 chevy 3/4 ton 4x4 402ci crewcab 3/4ton 94 gmc 1 ton dually crewcab 454ci 99 suburban 5.7 2001 500cc ski-doo mxz 95 500cc ski doo fan 650 bombardiar 4 wheeler

09-30-2002, 01:19 PM	#8
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	I thought it was the H-110 that came on duallies... __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?

09-30-2002, 01:45 PM	#9
jku72 Registered User Join Date: Jan 2002 Location: cornville, maine Posts: 659	I have an HO 72 under single rear wheels. But I do think the only difference is in the brake size. __________________ jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers

09-30-2002, 02:38 PM	#10
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Does it look like this?: Attached Images __________________ '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.

09-30-2002, 04:47 PM	#11
crew70 Registered User Join Date: Jan 2002 Location: shafer,mn,usa Posts: 316	yep,ho52. __________________ 70 chevy 3/4 ton 4x4 402ci crewcab 3/4ton 94 gmc 1 ton dually crewcab 454ci 99 suburban 5.7 2001 500cc ski-doo mxz 95 500cc ski doo fan 650 bombardiar 4 wheeler

09-30-2002, 09:51 PM	#12
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	There was an 11000 lbs gvw rear end that came on 1 ton duallies also... but it has ten studs on the drums. Still the truck was rated as 14000 lbs total. My dually has the 7500 lbs rear with the aux spring kit that made it a factory 11000lbs rear also but is 8 bolt stud pattern. 9/16 studs in 70 up I believe maybe just 71-72. The 11000 pound factory rear had vacyuum assist brake pods that mounted under the cab.... once you see one you will always remember the difference. Sorry no pic. __________________ 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.

09-30-2002, 09:59 PM	#13
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	OK...Why does my 7500 GVW 68 3/4 ton C20 with heavy duty coils, 4speed , and originally a factory big block have a dana 60 while all the other similarly equipped trucks I have seen have Eatons? Was there any formula to determine which trucks would have what rear ends? __________________ No truck :-(

09-30-2002, 11:49 PM	#14
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	If not mistaken, Danas were just another option that should have been opted for a more trucks than they were.

10-01-2002, 12:15 AM	#15
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	I just checked my option sheet. I got it along with the protectoplate, '68 service manual and warranty book. Not bad for $500. Other than HD rear springs and 396 engine there is nothing concerning the driveline. I did see a 67 in the boneyard the other day. I go once or twice a week . I've been a junkyard junky since I was 12. It had a eaton with a detroit locker and was optioned as such on the build sheet behind the rear seat as "extreme traction" or something like that. I check those . I am a dork . I'm thinking the Eaton was the option and the dana was the standard rear end under 3/4 tons. It might have been what they later called the heavy 3/4 ton option. __________________ No truck :-(

10-01-2002, 12:18 AM	#16
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Dana was not standard. Many things never made it to the option sheet. For example, the leaf/coil spring debate. I have never seen (in person) an option sheet that states one or the other, yet my GMC has coils in back, and I have seen a few leaf spring 1/2 ton chevys... Lots of mysteries.



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10-01-2002, 12:51 AM	#17
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Thats right. The build sheet had it listed as "Maximum Traction" Sounds rather ominous doesnt it? __________________ No truck :-(

10-01-2002, 09:18 AM	#18
Yellow Cheyenne Registered User Join Date: Jun 2001 Location: Eastern Kansas Posts: 488	Cobalt. Mine does look like that, except mine is a leaf spring set up. I will check for posi and ratio and let everyone know. Thanks to everyone for helping me out. __________________ '72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72) '56 Chevy short step V-8 (My dad bought it new!!) '70 Olds 442 convertible '70 Olds Rallye 350

10-01-2002, 01:42 PM	#19
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Well, I may catch heat for what I'm about to say, but it won't be the first time on this topic. longhornmail hit on it in his previous post. There's some large patches of grey area when it comes to the rear suspension/differential debate. It is NOT as standardized as people might think. The numbers on the differential you see in the picture above match to an HO72. Now before everyone jumps on me I checked this out, and technically you guys are correct about the configuration issues of leaf vs. coil sprung suspensions and 5200, 7200, and 11000 axles with or without the HD spring and/or overload spring options. All that aside the differential codes are what they are. Mine does not match the numbers for an HO52. Another thing. I think I mentioned in another post that these axles aren't technically "Eaton" axles. This is a source of confusion for a lot of people. Eaton made the carriers, and the optional posi units and such, but they didn't produce the whole axle. __________________ '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.

10-01-2002, 07:38 PM	#20
crew70 Registered User Join Date: Jan 2002 Location: shafer,mn,usa Posts: 316	ok i am going off of what I have learned from you guys on the board. anway can you tell from my code what it is? 3934635 __________________ 70 chevy 3/4 ton 4x4 402ci crewcab 3/4ton 94 gmc 1 ton dually crewcab 454ci 99 suburban 5.7 2001 500cc ski-doo mxz 95 500cc ski doo fan 650 bombardiar 4 wheeler

10-01-2002, 07:42 PM	#21
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	That's the casting number of the housing. Look in these areas for all of the codes. Like an engine you have to use them all to figure out what you have, and then there's a website that can tell you (don't remember the URL-sorry): Attached Images __________________ '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.

10-01-2002, 08:05 PM	#22
crew70 Registered User Join Date: Jan 2002 Location: shafer,mn,usa Posts: 316	ok heres what I found tpw1222g 3843067 3934635 couldn t find any numbers on the yoke like it says in your pic. __________________ 70 chevy 3/4 ton 4x4 402ci crewcab 3/4ton 94 gmc 1 ton dually crewcab 454ci 99 suburban 5.7 2001 500cc ski-doo mxz 95 500cc ski doo fan 650 bombardiar 4 wheeler

10-02-2002, 01:43 AM	#23
Yellow Cheyenne Registered User Join Date: Jun 2001 Location: Eastern Kansas Posts: 488	I opened mine up tonight. It is 4.10 non posi/non locker. It is in good shape if any one wants it. Otherwise it will go to junkyard this weekend. __________________ '72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72) '56 Chevy short step V-8 (My dad bought it new!!) '70 Olds 442 convertible '70 Olds Rallye 350

10-03-2002, 11:59 AM	#24
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	crew70: check inside the yoke. There should be a huge-a$$ nut inside that should have some codes stamped into it... We went to all this trouble for a junked differential? Oh well it's good info. __________________ '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.

10-03-2002, 12:42 PM	#25
Yellow Cheyenne Registered User Join Date: Jun 2001 Location: Eastern Kansas Posts: 488	It's only junk of nobody wants it. __________________ '72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72) '56 Chevy short step V-8 (My dad bought it new!!) '70 Olds 442 convertible '70 Olds Rallye 350

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