Help identify rear axle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mongo4298 · 01-21-2024, 07:05 PM

Hello, original owner of 1970 Chevy K20. I had the specs for the running gear but they have been misplaced. Before I place the truck on the market I want to address a few items that need attention. Pinion seal and differential cover gasket to start. The RPO code label on the glove box says G86 No Spin Rear Axle. The casting number on the differential is 3934665. I cannot find any numbers on the axle tubes. The Cover is 10 bolt. Approx. 13 inch width. The no- spin is a Eaton HO52. It has a 4 speed muncie SM 465 transmission. The front differential is a Dana 44. The transfer case is a NP 205 small cover/3bolts.
There is no tag on the rear cover thanks to the last time I had the gear oil changed.
Our local dealer is of no help so I would appreciate whatever help I can get. Thanks

**oneshotkyle** · 01-21-2024, 07:09 PM

Pics?

**Stocker** · 01-21-2024, 07:11 PM

I think you answered your own question when you mentioned the no-spin. Sounds like your axle is an HO52, common on K20s of that vintage. My '72 K20 has an Eaton HO52, and the cover does have 10 bolts. HTH

**LockDoc** · 01-21-2024, 09:59 PM

-
As far as the ratio, you might look on the passengers side axle tube and see if there is anything stamped there. (See pictures) If so use the first two or three letters and look them up on these charts.

https://www.67-72chevytrucks.com/vbo...d.php?t=578793
.

Sicklajoie · 01-21-2024, 10:14 PM

Well an HO52 rear is either a 4.11 or 4.56 correct?
Spin the tire once and see how many times the driveshaft spins.

**Stocker** · 01-22-2024, 12:33 AM

Since you'll have the diff cover off to replace the gasket, you can count the R&P teeth to get the exact ratio.

**MJN** · 01-22-2024, 01:07 PM

For the H0 axles the stamped code on top of the third member will tell you the build date and ratio.

mongo4298 · 01-26-2024, 07:03 PM

Thanks to everyone for your help. I'm having problems trying to locate the correct pinion seal. Local parts stores show pinion seals but there are several choices and each one is different. I contacted National Seals but they don't list it. My Chevy manuals show the seal but no part number. Is there a possibility that a member has a parts identification manual with actual GM numbers. I did find and purchase the correct cover gasket. Thanks

**MJN** · 01-26-2024, 07:14 PM

So if you have an Eaton style H0 axle with the big round 10 bolt cover then these are the pinion seals you need. One is the seal and the other is the felt packing. If you were able to find the correct cover gasket what axle do you have, Im not sure you posted that.

01-21-2024, 07:05 PM	#1
mongo4298 Registered User Join Date: Apr 2023 Location: Woodland, CA Posts: 15	Help identify rear axle Hello, original owner of 1970 Chevy K20. I had the specs for the running gear but they have been misplaced. Before I place the truck on the market I want to address a few items that need attention. Pinion seal and differential cover gasket to start. The RPO code label on the glove box says G86 No Spin Rear Axle. The casting number on the differential is 3934665. I cannot find any numbers on the axle tubes. The Cover is 10 bolt. Approx. 13 inch width. The no- spin is a Eaton HO52. It has a 4 speed muncie SM 465 transmission. The front differential is a Dana 44. The transfer case is a NP 205 small cover/3bolts. There is no tag on the rear cover thanks to the last time I had the gear oil changed. Our local dealer is of no help so I would appreciate whatever help I can get. Thanks

01-21-2024, 07:09 PM	#2
oneshotkyle Senior Member Join Date: Jan 2015 Location: central oregon Posts: 270	Re: Help identify rear axle Pics?

01-21-2024, 07:11 PM	#3
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,731	Re: Help identify rear axle I think you answered your own question when you mentioned the no-spin. Sounds like your axle is an HO52, common on K20s of that vintage. My '72 K20 has an Eaton HO52, and the cover does have 10 bolts. HTH __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

01-21-2024, 09:59 PM	#4
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,846	Re: Help identify rear axle - As far as the ratio, you might look on the passengers side axle tube and see if there is anything stamped there. (See pictures) If so use the first two or three letters and look them up on these charts. https://www.67-72chevytrucks.com/vbo...d.php?t=578793 . Attached Images __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

01-21-2024, 10:14 PM	#5
Sicklajoie The Niner Join Date: Nov 2010 Location: Broad Brook, CT Posts: 2,503	Re: Help identify rear axle Well an HO52 rear is either a 4.11 or 4.56 correct? Spin the tire once and see how many times the driveshaft spins. __________________ "A good racer is one whose head is in communication with his balls." - Richie Evans 1970 C/20 - 402/TH400/3.54s - 74K miles 2003 GMC Sierra 2500 - Wheatland Yellow Niner Progression Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=697183 Classic Trucks article: https://www.motortrend.com/features/...et-c20-driven/

01-22-2024, 12:33 AM	#6
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,731	Re: Help identify rear axle Since you'll have the diff cover off to replace the gasket, you can count the R&P teeth to get the exact ratio. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

01-22-2024, 01:07 PM	#7
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	Re: Help identify rear axle For the H0 axles the stamped code on top of the third member will tell you the build date and ratio. Attached Images __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com

01-26-2024, 07:03 PM	#8
mongo4298 Registered User Join Date: Apr 2023 Location: Woodland, CA Posts: 15	Re: Help identify rear axle Thanks to everyone for your help. I'm having problems trying to locate the correct pinion seal. Local parts stores show pinion seals but there are several choices and each one is different. I contacted National Seals but they don't list it. My Chevy manuals show the seal but no part number. Is there a possibility that a member has a parts identification manual with actual GM numbers. I did find and purchase the correct cover gasket. Thanks

01-26-2024, 07:14 PM	#9
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	Re: Help identify rear axle So if you have an Eaton style H0 axle with the big round 10 bolt cover then these are the pinion seals you need. One is the seal and the other is the felt packing. If you were able to find the correct cover gasket what axle do you have, Im not sure you posted that. Attached Images __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com



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