Rear axle ID - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BR3W CITY · 02-17-2011, 05:34 PM

The weather has broken enough that I can get back out in the garage, but I need to get some info together.

My rear axle is a 12-bolt, and I was told when I got the truck that its a 3:73 rear end, with posi. I have the code " N 3856525" stamped into the gusset. I can't seem to find a site to decode this. Is this a truck or car rear end?

Rear brakes are drums, it has 5-lugs, and its on my 66 with trailing arms. I couldn't tell if the rear end ever had leaf perches, since it was cleaned up and painted by the po. Its got Moser axles, and I was told it was a 3:73 posi rear. Anyone have a clue what rear this might be?
Thanks!

**john** · 02-17-2011, 08:19 PM

On a 12 bolt, you will find the axle code on the pass side tube. Look about six-eight inches out from the punkin, there will be some letters stamped in the tube on the top side a little bit to the front. Post the letters and we can decode them. Hard to say what is actually in there on an old truck without pulling the cover and looking.

**Captainfab** · 02-18-2011, 01:08 AM

The code on the axle tube is only going to tell you what GM put in that housing. If it is known to have Moser axles, the only way to know for sure what else is inside, is to pull the cover and have a look. It's easy to do and it'll only cost you a cover gasket and a couple quarts of gear oil. Chances are the oil needs changed anyway.

BR3W CITY · 02-18-2011, 12:28 PM

Ya, I have no problem pulling the cover. I'm not really worried about whether or not its a 3:73, I'm more concerned as to WHAT the rear end was out of. The pass axle code should tell me that correct?

Thanks

ka_jd7and1 · 02-18-2011, 02:52 PM

A Yahoo search of the number you posted brought up a few pages with '64/'65/'66 trucks that had that rear end. Can't tell you for sure if it's original to the truck.

BR3W CITY · 02-19-2011, 01:01 AM

I found the other code stamped in the axle. It reads HA 05020 W.

**john** · 02-19-2011, 02:17 PM

HA code was used in 1969 C-10 12 bolt. 3:73.1 ratio

BR3W CITY · 02-19-2011, 02:54 PM

Thanks very much john!

ChuckyC · 02-21-2014, 06:59 PM

The code on the differential that I just purchased is HA 0110k, can someone help me to identify it?

BR3W CITY · 02-21-2014, 09:19 PM

What I can find shows a 67-68 truck rear end with a 3:73 non-posi
http://www.gmcpauls.com/67-72_chevy.htm

ChuckyC · 02-21-2014, 09:38 PM

thanks man, I really appreciate it. i have been searching all over and couldn't find anything.

BR3W CITY · 02-22-2014, 01:30 AM

haha, I only saw your post because it popped up on my old sub'd threads, since I was the original poster. You really found an old one too!

If you google your axle ID, no info will come up, mainly because the specific code may not match enough others. If you look at the GMC pauls site, and a few others, you can start to get the decoding system down. Main thing is to look at those first to letters, the "HA"...which corresponds to the 3:73 gearset rear. The only trouble is finding the correct ledger to compare it to.

**The Rocknrod** · 06-17-2015, 03:07 PM

I have a WC 6 17. DOes that mean a Posi 3.73?
And what does the 6 17 mean?

1963c-10 · 06-19-2015, 10:56 AM

WC = 3.73 posi June 17

wolken · 10-31-2016, 09:18 PM

My 12 bolt reads TBA W001 2

Can someone please decode this for me I have been looking all over. I broke and axle and I know this rear end does not belong to this truck.

**Captainfab** · 10-31-2016, 11:35 PM

To get a new axle all you need to know is the number of wheel studs and the bolt circle, the length plus the spline count.

wolken · 10-31-2016, 11:43 PM

Have you been to a parts store lately? The last time I went in to get a clutch master cylinder the kid actually asked me if I had an automatic or manual... It would be much easier if I could tell him what the axle was in or at least give them a year.

**Captainfab** · 10-31-2016, 11:49 PM

Yes I have and I certainly would not even consider going to one of the chain parts stores to get an axle for an older truck. Get the info I mentioned above and then look online and see what you can find. You must have some sort of idea what the differential is? What year of truck is it in now? Is it a 2wd or a 4wd? What makes you think it is not original?

Take a look here.

https://www.yukongear.com/partslist....SpotlightID=14

wolken · 11-01-2016, 11:17 AM

It's 4wd its a 12 bolt posi which wasn't offered in 85. Why are you even arguing the point? I just asked what the axle code translated to. The truck is a pile and I need a new axle. I don't want to wait a week ordering online and getting the wrong thing. A big box box store can help me just fine if I can find the year the rear end is from.

**Captainfab** · 11-01-2016, 11:31 PM

Just trying to help you figure out what axle you need since there does not seem to be a listing with that build code.

A 4wd 12 bolt narrows it down to the years of '63-'79. There are only 2 different lengths of axles used within those years.

wolken · 11-01-2016, 11:39 PM

OK well that's what's the axle says. I ordered a 75 one I'll find out tomorrow if I chose well.

**MySons68C20** · 11-03-2016, 11:00 PM

Thanks Capt, I appreciate your help even if some people don't

Chevy Apache · 11-23-2016, 05:54 PM

Hi trying to find what ratio is on my axle this is the number I have found gm73 stamped on the diff casing one side

And the other side it has this number 3896839 and there is an n underneath that thanks any advice would be great thanks Pete

**Captainfab** · 11-23-2016, 11:41 PM

Those numbers are just casting numbers and will not tell you anything about what GM put inside the housing 50+ years ago. For that info you will need the build code stamped on top of the passenger side axle tube. There is no guarantee that the original parts are still inside. Myself, I would just pull the cover and have a look. More than likely the oil needs changed anyway.The differential is one of the most neglected parts of a vehicle.

Quote:

Originally Posted by Chevy Apache

Hi trying to find what ratio is on my axle this is the number I have found gm73 stamped on the diff casing one side

And the other side it has this number 3896839 and there is an n underneath that thanks any advice would be great thanks Pete

Chevy Apache · 11-24-2016, 12:59 PM

Quote:

Originally Posted by Captainfab

Those numbers are just casting numbers and will not tell you anything about what GM put inside the housing 50+ years ago. For that info you will need the build code stamped on top of the passenger side axle tube. There is no guarantee that the original parts are still inside. Myself, I would just pull the cover and have a look. More than likely the oil needs changed anyway.The differential is one of the most neglected parts of a vehicle.

Thanks captain a have since come across this number which way help.
Kax w25511 thank for your help Pete

02-17-2011, 05:34 PM	#1
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Rear axle ID The weather has broken enough that I can get back out in the garage, but I need to get some info together. My rear axle is a 12-bolt, and I was told when I got the truck that its a 3:73 rear end, with posi. I have the code " N 3856525" stamped into the gusset. I can't seem to find a site to decode this. Is this a truck or car rear end? Rear brakes are drums, it has 5-lugs, and its on my 66 with trailing arms. I couldn't tell if the rear end ever had leaf perches, since it was cleaned up and painted by the po. Its got Moser axles, and I was told it was a 3:73 posi rear. Anyone have a clue what rear this might be? Thanks! __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-17-2011, 08:19 PM	#2
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Rear axle ID On a 12 bolt, you will find the axle code on the pass side tube. Look about six-eight inches out from the punkin, there will be some letters stamped in the tube on the top side a little bit to the front. Post the letters and we can decode them. Hard to say what is actually in there on an old truck without pulling the cover and looking. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

02-18-2011, 01:08 AM	#3
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Rear axle ID The code on the axle tube is only going to tell you what GM put in that housing. If it is known to have Moser axles, the only way to know for sure what else is inside, is to pull the cover and have a look. It's easy to do and it'll only cost you a cover gasket and a couple quarts of gear oil. Chances are the oil needs changed anyway. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

02-18-2011, 12:28 PM	#4
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Rear axle ID Ya, I have no problem pulling the cover. I'm not really worried about whether or not its a 3:73, I'm more concerned as to WHAT the rear end was out of. The pass axle code should tell me that correct? Thanks __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-18-2011, 02:52 PM	#5
ka_jd7and1 is a fungineer Join Date: Jan 2009 Location: Bakersfield, CA Posts: 795	Re: Rear axle ID A Yahoo search of the number you posted brought up a few pages with '64/'65/'66 trucks that had that rear end. Can't tell you for sure if it's original to the truck. __________________ 2003 S10, 2.2 auto- the daily driver, currently with a 2"/2" drop and some minor engine bolt-ons 1978 Impala 2-door, race 350/T350 - the new race car, in progress 1968 Chevy C10 longbed- 3/5 drop, currently undergoing a heart transplant

02-19-2011, 01:01 AM	#6
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Rear axle ID I found the other code stamped in the axle. It reads HA 05020 W. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-19-2011, 02:17 PM	#7
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Rear axle ID HA code was used in 1969 C-10 12 bolt. 3:73.1 ratio __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

02-19-2011, 02:54 PM	#8
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Rear axle ID Thanks very much john! __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-21-2014, 06:59 PM	#9
ChuckyC Registered User Join Date: Feb 2012 Location: Tahlequah, OK Posts: 4	Re: Rear axle ID The code on the differential that I just purchased is HA 0110k, can someone help me to identify it?

02-21-2014, 09:19 PM	#10
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Rear axle ID What I can find shows a 67-68 truck rear end with a 3:73 non-posi http://www.gmcpauls.com/67-72_chevy.htm __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-21-2014, 09:38 PM	#11
ChuckyC Registered User Join Date: Feb 2012 Location: Tahlequah, OK Posts: 4	Re: Rear axle ID thanks man, I really appreciate it. i have been searching all over and couldn't find anything.

02-22-2014, 01:30 AM	#12
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Rear axle ID haha, I only saw your post because it popped up on my old sub'd threads, since I was the original poster. You really found an old one too! If you google your axle ID, no info will come up, mainly because the specific code may not match enough others. If you look at the GMC pauls site, and a few others, you can start to get the decoding system down. Main thing is to look at those first to letters, the "HA"...which corresponds to the 3:73 gearset rear. The only trouble is finding the correct ledger to compare it to. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

06-17-2015, 03:07 PM	#13
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: Rear axle ID I have a WC 6 17. DOes that mean a Posi 3.73? And what does the 6 17 mean? __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

06-19-2015, 10:56 AM	#14
1963c-10 Registered User Join Date: Nov 2011 Location: fayetteville nc Posts: 10,338	Re: Rear axle ID WC = 3.73 posi June 17 Attached Images __________________ 1963 Short bed step side SBW 427 big block and borg warner T-16 HD 3 speed manual http://67-72chevytrucks.com/vboard/s...d.php?t=519869 1963 Short bed fleetside BBW 348 1st gen big block w/Powerglide http://67-72chevytrucks.com/vboard/s...d.php?t=619024 1964 Short bed trailer

10-31-2016, 09:18 PM	#15
wolken Registered User Join Date: Oct 2016 Location: Brighton IL Posts: 4	Re: Rear axle ID My 12 bolt reads TBA W001 2 Can someone please decode this for me I have been looking all over. I broke and axle and I know this rear end does not belong to this truck.



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10-31-2016, 11:35 PM	#16
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Rear axle ID To get a new axle all you need to know is the number of wheel studs and the bolt circle, the length plus the spline count. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

10-31-2016, 11:43 PM	#17
wolken Registered User Join Date: Oct 2016 Location: Brighton IL Posts: 4	Re: Rear axle ID Have you been to a parts store lately? The last time I went in to get a clutch master cylinder the kid actually asked me if I had an automatic or manual... It would be much easier if I could tell him what the axle was in or at least give them a year.

10-31-2016, 11:49 PM	#18
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Rear axle ID Yes I have and I certainly would not even consider going to one of the chain parts stores to get an axle for an older truck. Get the info I mentioned above and then look online and see what you can find. You must have some sort of idea what the differential is? What year of truck is it in now? Is it a 2wd or a 4wd? What makes you think it is not original? Take a look here. https://www.yukongear.com/partslist....SpotlightID=14 __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

11-01-2016, 11:17 AM	#19
wolken Registered User Join Date: Oct 2016 Location: Brighton IL Posts: 4	Re: Rear axle ID It's 4wd its a 12 bolt posi which wasn't offered in 85. Why are you even arguing the point? I just asked what the axle code translated to. The truck is a pile and I need a new axle. I don't want to wait a week ordering online and getting the wrong thing. A big box box store can help me just fine if I can find the year the rear end is from.

11-01-2016, 11:31 PM	#20
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Rear axle ID Just trying to help you figure out what axle you need since there does not seem to be a listing with that build code. A 4wd 12 bolt narrows it down to the years of '63-'79. There are only 2 different lengths of axles used within those years. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

11-01-2016, 11:39 PM	#21
wolken Registered User Join Date: Oct 2016 Location: Brighton IL Posts: 4	Re: Rear axle ID OK well that's what's the axle says. I ordered a 75 one I'll find out tomorrow if I chose well.

11-03-2016, 11:00 PM	#22
MySons68C20 Senior Member Join Date: Sep 2014 Location: Wenatchee, Wa Posts: 897	Re: Rear axle ID Thanks Capt, I appreciate your help even if some people don't

11-23-2016, 05:54 PM	#23
Chevy Apache Registered User Join Date: Apr 2016 Location: England Posts: 173	Re: Rear axle ID Hi trying to find what ratio is on my axle this is the number I have found gm73 stamped on the diff casing one side And the other side it has this number 3896839 and there is an n underneath that thanks any advice would be great thanks Pete

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