Need help identifying 1972 k20 rearend. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

lutjanid · 11-23-2015, 05:24 PM

The front axle is a Dana 44 and the numbers were easy to find. Not having any luck with the rear. I believe it to be the factory axle, but can't find any markings. Thanks for the help.

racerop · 11-23-2015, 05:28 PM

That's An Eaton

**dozerbill72** · 11-23-2015, 05:40 PM

On the drivers side of the pinion on the front if there is a bolt with a jam nut. the bolt would be pointing towards the drivers tire. It is a HO72 if it does not have that bolt and nut it's a HO52.

**Stocker** · 11-23-2015, 05:49 PM

Quote:

Originally Posted by dozerbill72

On the drivers side of the pinion on the front if there is a bolt with a jam nut. the bolt would be pointing towards the drivers tire. It is a HO72 if it does not have that bolt and nut it's a HO52.

All HO72s (1-ton trucks) have the load bolt.... some HO52s (3/4-ton trucks) have it, and some do not.

**dozerbill72** · 11-23-2015, 05:53 PM

Stocker, how do you tell them apart if it is a 52 with a preload bolt?

**Stocker** · 11-23-2015, 07:55 PM

Well, the hard parts are supposed to be mostly the same. Only difference I am aware of is the brakes, which are bigger on HO72s. And possibly some bearings, but a search is needed to find that info.

**special-K** · 11-23-2015, 08:26 PM

They are the same rear with different brakes and wheel bearings. I'm sure it's the HO52 Corporate rear since that's what would have come in your K/20. Sure,maybe someone changed it. But they are the same rear anyway. The only HO72 it could be would be from a single wheel C/30. Very few cab & chassis SRW C/30s were sold, mostly stepsides and Longhorns

lutjanid · 11-23-2015, 08:31 PM

It is original to the truck, so that would make it the HO52. I would like to change out the diffs from 4.10 to 3.73, but it doesn't look that easy with the HO52. Dana 44 up front.

swamp rat · 11-24-2015, 12:23 AM

Quote:

Originally Posted by dozerbill72

On the drivers side of the pinion on the front if there is a bolt with a jam nut. the bolt would be pointing towards the drivers tire. It is a HO72 if it does not have that bolt and nut it's a HO52.

Not always true from everything i have read on this forum.. EDIT: Never mind i see it was already talked about..

swamp rat · 11-24-2015, 12:27 AM

I would really like to see some pic's of the HO-72 brakes, My K20 has the larger finned drums so i origionally thought it was an HO-72.

11-23-2015, 05:24 PM	#1
lutjanid Registered User Join Date: Nov 2015 Location: Granbury, TX Posts: 23	Need help identifying 1972 k20 rearend. The front axle is a Dana 44 and the numbers were easy to find. Not having any luck with the rear. I believe it to be the factory axle, but can't find any markings. Thanks for the help. Attached Images

11-23-2015, 05:28 PM	#2
racerop Registered User Join Date: Jul 2015 Location: Laurel Springs, NJ Posts: 94	Re: Need help identifying 1972 k20 rearend. That's An Eaton

11-23-2015, 05:40 PM	#3
dozerbill72 Senior Member Join Date: Oct 2015 Location: Berryville Arkansas Posts: 402	Re: Need help identifying 1972 k20 rearend. On the drivers side of the pinion on the front if there is a bolt with a jam nut. the bolt would be pointing towards the drivers tire. It is a HO72 if it does not have that bolt and nut it's a HO52.

11-23-2015, 05:53 PM	#5
dozerbill72 Senior Member Join Date: Oct 2015 Location: Berryville Arkansas Posts: 402	Re: Need help identifying 1972 k20 rearend. Stocker, how do you tell them apart if it is a 52 with a preload bolt?

11-23-2015, 07:55 PM	#6
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,722	Re: Need help identifying 1972 k20 rearend. Well, the hard parts are supposed to be mostly the same. Only difference I am aware of is the brakes, which are bigger on HO72s. And possibly some bearings, but a search is needed to find that info. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

11-23-2015, 08:26 PM	#7
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Need help identifying 1972 k20 rearend. They are the same rear with different brakes and wheel bearings. I'm sure it's the HO52 Corporate rear since that's what would have come in your K/20. Sure,maybe someone changed it. But they are the same rear anyway. The only HO72 it could be would be from a single wheel C/30. Very few cab & chassis SRW C/30s were sold, mostly stepsides and Longhorns __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

11-23-2015, 08:31 PM	#8
lutjanid Registered User Join Date: Nov 2015 Location: Granbury, TX Posts: 23	Re: Need help identifying 1972 k20 rearend. It is original to the truck, so that would make it the HO52. I would like to change out the diffs from 4.10 to 3.73, but it doesn't look that easy with the HO52. Dana 44 up front.

11-24-2015, 12:27 AM	#10
swamp rat Registered User Join Date: Oct 2007 Location: Spanaway Posts: 8,451	Re: Need help identifying 1972 k20 rearend. I would really like to see some pic's of the HO-72 brakes, My K20 has the larger finned drums so i origionally thought it was an HO-72. __________________ Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's



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