Need help to identify differential - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*Peanutbutter* · 11-21-2014, 10:42 PM

Hi guys, I don't seen to be able to spend much time here latetly but maybe things will get better. I finally got started work on my 1966 C80 series napco, got it down to bare frame to start sandblasting. I'm more concerned about the front axle, in dire need of new ring and pinion but having trouble identifying. Its a rather large square tube housing with napco tag riveted to the front but it looks like they used 1960s eaton carrier in napco housing. I understand eaton had five differentials starting with the HO52, then HO72, then an 11000 lb, 15000, and last is 17000lb. My ratio is 7.20 with 5 and 36 teeth and I thought it might be the 17 but when I checked the only single speed I had discovered it was to big. Now I'm thinking it must be the 1100 or 15000. My big single I checked tonight is oblong and bolts up with 13 bolts, the one I need is completely round and bolts to housing with 10 bolts. Need info to tell difference between the 11, 15, and 17000lb. Will post some pics tomorrow night, maybe they will help. thanks, Wes

mrolds88 · 11-22-2014, 10:56 AM

Did Napco exclusively use Eaton/GM? Since they weren't "brand loyal" as far as customers, maybe they had several suppliers. What about Spicer?

*Peanutbutter* · 11-22-2014, 12:35 PM

I don't think I can answer that, all I can tell you is this carrier looks identical to the HO52 and 72s in my 64,65 3/4 ton pickups except its half again bigger, it has a load bolt just like the 3/4 ton carrier. I'll send pics tonight, you can only tell the difference if you had mine side by side with HO72. If you look at picks of the carrier to housing and tin cover plate gaskets you can't tell the difference unless they are next to each other. My carrier measures 14 inchs across, the HO72 probably measures around 12 inchs. They both use 10 bolts on cover and carrier, mine looks like it should be in a 1 1/2 ton. More tonight.

j.kirn · 11-23-2014, 12:38 AM

ask over at the napco website

mrolds88 · 11-26-2014, 12:01 PM

PB, I have a PM for you.

mrolds88 · 11-28-2014, 07:14 PM

Also one other thought. H110. This was the 11000lb big brother of the H052 and H072.

11-21-2014, 10:42 PM	#1
Peanutbutter Account Suspended Join Date: Feb 2013 Location: Mesa, Colorado Posts: 450	Need help to identify differential Hi guys, I don't seen to be able to spend much time here latetly but maybe things will get better. I finally got started work on my 1966 C80 series napco, got it down to bare frame to start sandblasting. I'm more concerned about the front axle, in dire need of new ring and pinion but having trouble identifying. Its a rather large square tube housing with napco tag riveted to the front but it looks like they used 1960s eaton carrier in napco housing. I understand eaton had five differentials starting with the HO52, then HO72, then an 11000 lb, 15000, and last is 17000lb. My ratio is 7.20 with 5 and 36 teeth and I thought it might be the 17 but when I checked the only single speed I had discovered it was to big. Now I'm thinking it must be the 1100 or 15000. My big single I checked tonight is oblong and bolts up with 13 bolts, the one I need is completely round and bolts to housing with 10 bolts. Need info to tell difference between the 11, 15, and 17000lb. Will post some pics tomorrow night, maybe they will help. thanks, Wes

11-22-2014, 10:56 AM	#2
mrolds88 Registered User Join Date: Jul 2011 Location: WV Posts: 946	Re: Need help to identify differential Did Napco exclusively use Eaton/GM? Since they weren't "brand loyal" as far as customers, maybe they had several suppliers. What about Spicer? __________________ 72 GMC C2500 402/Th400 first truck (still have) 77 GMC C3500 CC dually Sold 70 C50 dump truck "Rusty" 87 K10 Suburban Sold 93 K2500 xcab 6.5TD 96 GMC K2500 Suburban 6.5 TD

11-22-2014, 12:35 PM	#3
Peanutbutter Account Suspended Join Date: Feb 2013 Location: Mesa, Colorado Posts: 450	Re: Need help to identify differential I don't think I can answer that, all I can tell you is this carrier looks identical to the HO52 and 72s in my 64,65 3/4 ton pickups except its half again bigger, it has a load bolt just like the 3/4 ton carrier. I'll send pics tonight, you can only tell the difference if you had mine side by side with HO72. If you look at picks of the carrier to housing and tin cover plate gaskets you can't tell the difference unless they are next to each other. My carrier measures 14 inchs across, the HO72 probably measures around 12 inchs. They both use 10 bolts on cover and carrier, mine looks like it should be in a 1 1/2 ton. More tonight.

11-23-2014, 12:38 AM	#4
j.kirn Registered User Join Date: Jun 2006 Location: MO. Posts: 970	Re: Need help to identify differential ask over at the napco website

11-26-2014, 12:01 PM	#5
mrolds88 Registered User Join Date: Jul 2011 Location: WV Posts: 946	Re: Need help to identify differential PB, I have a PM for you. __________________ 72 GMC C2500 402/Th400 first truck (still have) 77 GMC C3500 CC dually Sold 70 C50 dump truck "Rusty" 87 K10 Suburban Sold 93 K2500 xcab 6.5TD 96 GMC K2500 Suburban 6.5 TD

11-28-2014, 07:14 PM	#6
mrolds88 Registered User Join Date: Jul 2011 Location: WV Posts: 946	Re: Need help to identify differential Also one other thought. H110. This was the 11000lb big brother of the H052 and H072. __________________ 72 GMC C2500 402/Th400 first truck (still have) 77 GMC C3500 CC dually Sold 70 C50 dump truck "Rusty" 87 K10 Suburban Sold 93 K2500 xcab 6.5TD 96 GMC K2500 Suburban 6.5 TD



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.