HO52 rebuild pitted gears - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**MJN** · 11-22-2022, 04:49 PM

So, yesterday I pulled the third member out of the housing from my '56 3600 NAPCO pickup, 4.57 gears open carrier. I was going to have it rebuilt- I have all the bearings, shims, seals, gasket, etc. it turns smooth, not much play in the pinion but the ring gear is pretty pitted. I'm not sure if these are worth having rebuilt at this point or if I should start searching for another differential. I'd like to keep the third member since its original to the truck but its not a deal breaker. Thoughts on moving ahead with rebuilding this gear set or tracking down a better ring and pinion?

Bigdav160 · 11-22-2022, 06:40 PM

I've actually run gears like that before (flood vehicles) and never had a problem (YMMV)

**MJN** · 11-23-2022, 09:49 PM

The upside is the gears aren't worn funky and everything else is in good shape. For what it will be used for and how often they'll probably be fine as is just figured I'd get any second opinions.

crazy longhorn · 11-26-2022, 06:01 PM

I have also run pitted gears like that, I would run them....see how they act? After a few miles(500-1000), change the gearlube again. CrazyL

whitedog76 · 11-26-2022, 09:07 PM

If you feel like you need to swap gears out, let me know, I have a center section.

**truckdude239** · 11-27-2022, 02:49 PM

thats what my 12 bolt looks like i flushred the housing and added new fuidl 3k miels so far no noise or anything

Short 3/4 · 11-28-2022, 04:03 PM

Like others above, I ran some that looked like that in a DD for several decades. In fact, as it wore in over the years it got a little quieter. I would think that there are plenty of other noises in that truck to drown out any from the diff .Bottom line, other than some possible noise, no other reason to R&R it, you’ll never ware it out.

That said, if you are going through it anyway, would be easy enough to swap in a new R&P at that time and keep the original case. Plenty of misguided individuals out there replacing perfectly good HO’s and 4:56 was the most common ratio. Shouldn’t be too hard to find.

Good luck with the project
Tom

**Ironangel** · 11-29-2022, 05:49 AM

Those HO52 and HO72 differentials are practically indestructible. If the bearings and races look good, refill it and run it.

11-22-2022, 04:49 PM	#1
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 2,959	HO52 rebuild pitted gears So, yesterday I pulled the third member out of the housing from my '56 3600 NAPCO pickup, 4.57 gears open carrier. I was going to have it rebuilt- I have all the bearings, shims, seals, gasket, etc. it turns smooth, not much play in the pinion but the ring gear is pretty pitted. I'm not sure if these are worth having rebuilt at this point or if I should start searching for another differential. I'd like to keep the third member since its original to the truck but its not a deal breaker. Thoughts on moving ahead with rebuilding this gear set or tracking down a better ring and pinion? 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

11-22-2022, 06:40 PM	#2
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: HO52 rebuild pitted gears I've actually run gears like that before (flood vehicles) and never had a problem (YMMV) __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

11-23-2022, 09:49 PM	#3
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 2,959	Re: HO52 rebuild pitted gears The upside is the gears aren't worn funky and everything else is in good shape. For what it will be used for and how often they'll probably be fine as is just figured I'd get any second opinions. __________________ '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

11-26-2022, 06:01 PM	#4
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: HO52 rebuild pitted gears I have also run pitted gears like that, I would run them....see how they act? After a few miles(500-1000), change the gearlube again. CrazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

11-26-2022, 09:07 PM	#5
whitedog76 Registered User Join Date: Jan 2014 Location: Peoria, IL Posts: 1,450	Re: HO52 rebuild pitted gears If you feel like you need to swap gears out, let me know, I have a center section.

11-27-2022, 02:49 PM	#6
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,217	Re: HO52 rebuild pitted gears thats what my 12 bolt looks like i flushred the housing and added new fuidl 3k miels so far no noise or anything __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

11-28-2022, 04:03 PM	#7
Short 3/4 Registered User Join Date: Jan 2017 Location: Los Osos Ca Posts: 528	Re: HO52 rebuild pitted gears Like others above, I ran some that looked like that in a DD for several decades. In fact, as it wore in over the years it got a little quieter. I would think that there are plenty of other noises in that truck to drown out any from the diff .Bottom line, other than some possible noise, no other reason to R&R it, you’ll never ware it out. That said, if you are going through it anyway, would be easy enough to swap in a new R&P at that time and keep the original case. Plenty of misguided individuals out there replacing perfectly good HO’s and 4:56 was the most common ratio. Shouldn’t be too hard to find. Good luck with the project Tom __________________ 65 short stepside K10 292-SM420-T221 8 lug closed D44 front NoSpin HO72 4.10 rear

11-29-2022, 05:49 AM	#8
Ironangel Senior Member Join Date: Feb 2010 Location: Falls City, Nebraska "100 Miles From Nowhere" Posts: 2,219	Re: HO52 rebuild pitted gears Those HO52 and HO72 differentials are practically indestructible. If the bearings and races look good, refill it and run it. __________________ Michael of the clan Hill, "Two Seventy Two's" 71 1-ton Dually 350 4-Speed 71 C/50 Grain Truck, 350 Split-Axle 4-Speed 02 3/4 ton Express 14 Indian Chief Vintage 1952 Ford 8N, "Only Ford Allowed On The Property" "Be American, Buy American"



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