12 bolt ID - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Sammy · 09-26-2011, 04:55 PM

12 BOLT rearend ID.

These numbers are located on the axle tubes on a 5 Lug Rear from a 6 Cyl 1971 chevy S/B truck.

D242 1234567890 CON2

No other tags or ID marks on this thing. If you know how to ID this it will help me thanks.

Sammy · 09-26-2011, 05:25 PM

pic if it helps

**john** · 09-26-2011, 05:45 PM

The code numbers are stamped on the pass side axle tube on the top side. they aren't always stamped very deep, so you need to wire brush the tube to find them.

Lee H · 09-26-2011, 06:50 PM

It's good to decode the stampings to see what the truck was born with. Just don't assume that's what's in it now.
Posted via Mobile Device

longbed67 · 09-26-2011, 07:10 PM

Here is a copy of what another member wrote in another thread on here I copy and pasted into a word doc I cant remember who did it but it is accurate.

C10 Rear axle codes

"I found some axle codes. The code is stamped on the top passenger side axle tube. The code on my rear end reads HB 03 25 W. The HB is the gear ratio, 03 is the month it was built and the 25 is the day. These codes are for the
C-10 series. "

HB,LL,RA.TR,TT,TU are 3.07s

HA,HJ,HQ,MF,TQ,MI,MK are 3.73s

HK,HL,HR,ME,MG,TS are 4.11s

HC,HN,MU are 3.73 Posi

HO,HP,JQ, are 4.11 Posi

slikside · 09-26-2011, 09:11 PM

subscribed

Sammy · 09-27-2011, 02:56 PM

Interesting, done brushing, cleaning and found this: on R/H upper side of Tube:
RHC W144 2
Does this mean it's a posi 373?
If so I'll be stoked..Interesting as the truck was a plain jane 71 6 Cyl truck with only two items on the spid: Red/white paint & Gage cluster. Didn't even have a Cig lighter just the delete plug in the dash. Whatever I got a good deal for a $50 bill.

stomper · 09-27-2011, 03:54 PM

Subscribed

Sammy · 09-27-2011, 04:00 PM

I looked all over the place on the www didn't find the codes listed by LONGBED67. Plenty of other stuff just nothing corresponding to my codes (RHC). Jacking one side up attempting to spin a wheel is a no go. I will assume it's a posi. Will know more once the cover comes off for fluid change.

**john** · 09-27-2011, 04:13 PM

My book shows RHC as a 1972 3.73:1 ratio. The 1971 ratios all start with the letter "T".

longbed67 · 09-27-2011, 09:59 PM

Yes should be a 3.73 posi unless someone changed the guts

stomper · 09-28-2011, 12:47 PM

How does one decode the stamping after after the ratio code? I assume that's the date? I have one stamped "HC" (with an E) below it and what looks like "1027K" after. 3.73 posi is still in it and was told it's a '68. It's narrow. I have a pic but can't post from my Droid.
Posted via Mobile Device

stomper · 09-28-2011, 01:15 PM

Pic. Sammy, Hope it's Ok if I kind of hyjack this thread. I can confirm another HC coded 3.73 posi. I reread posts closer and see Longbed67 already told us how to decode the month and day. Looks like I have an October, 27th built rear but what's the year? Does the "K" indicate that somehow? ..and Sammy's "W144 2" doesn't seem to compute.

Sammy · 09-30-2011, 01:35 PM

From another site I gathered W was a plant manufactures code 1 was last digit of the year and 44 th day of production and 2 as 2nd shift. But who knows. Most important for me was the gear ratio..and the year of 71 which I knew as I removed it.
Your "K" doesn't make any since to me at the end..My W is in the front..unless they just put them anywhere to indicate the plant assy point.

Hijacking threads are a great way to learn stuff...from each other..so drive on and keep truckin..

VA72C10 · 10-03-2012, 02:39 AM

Old thread....but What about

HE1 11w

Or
TDA?

Two different axles I have that I can't find the codes listed anywhere...
Posted via Mobile Device

**Already Gone** · 10-03-2012, 06:22 AM

subscribed
Posted via Mobile Device

jjzepplin · 10-03-2012, 08:03 AM

Got two I need to decode to see which I will keep. One is def posi unsure of other. Can you tell ratio from stampings on ring gear? I seem to recall the guy I bought my 14 bolt from pulled the cover and showed me the 4.10 stamp.

mechanic58 · 04-07-2013, 11:47 AM

Man - I have been searching all over the internet for information about these stamp codes and I just can't find anything. I am looking at an axle from a '65 Chevy pickup that is stamped "WE327" on the tube. I can't find ANY information on that particular code. I want to find out the gear ratio. The axle is fairly far from me or I'd just go take the cover off and find out.

Boatracer · 05-25-2016, 10:40 AM

Also looking for axle code "TDA"

**LockDoc** · 05-25-2016, 10:43 AM

Quote:

Originally Posted by Boatracer

Also looking for axle code "TDA"

Look in this thread...

http://67-72chevytrucks.com/vboard/s...d.php?t=578793

The 3 letter codes start with 1970

LockDoc

Boatracer · 05-25-2016, 10:49 AM

Thank you!

**LockDoc** · 05-25-2016, 10:59 AM

Quote:

Originally Posted by Boatracer

Thank you!

No problem....

LockDoc

09-26-2011, 04:55 PM	#1
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	12 bolt ID 12 BOLT rearend ID. These numbers are located on the axle tubes on a 5 Lug Rear from a 6 Cyl 1971 chevy S/B truck. D242 1234567890 CON2 No other tags or ID marks on this thing. If you know how to ID this it will help me thanks. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

09-26-2011, 05:25 PM	#2
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: 12 bolt ID pic if it helps Attached Images __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

09-26-2011, 05:45 PM	#3
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: 12 bolt ID The code numbers are stamped on the pass side axle tube on the top side. they aren't always stamped very deep, so you need to wire brush the tube to find them. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

09-26-2011, 06:50 PM	#4
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,141	Re: 12 bolt ID It's good to decode the stampings to see what the truck was born with. Just don't assume that's what's in it now. Posted via Mobile Device __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

09-26-2011, 07:10 PM	#5
longbed67 Registered User Join Date: Jun 2011 Location: Monroe, WI Posts: 1,415	Re: 12 bolt ID Here is a copy of what another member wrote in another thread on here I copy and pasted into a word doc I cant remember who did it but it is accurate. C10 Rear axle codes "I found some axle codes. The code is stamped on the top passenger side axle tube. The code on my rear end reads HB 03 25 W. The HB is the gear ratio, 03 is the month it was built and the 25 is the day. These codes are for the C-10 series. " HB,LL,RA.TR,TT,TU are 3.07s HA,HJ,HQ,MF,TQ,MI,MK are 3.73s HK,HL,HR,ME,MG,TS are 4.11s HC,HN,MU are 3.73 Posi HO,HP,JQ, are 4.11 Posi

09-26-2011, 09:11 PM	#6
slikside Registered User Join Date: Jun 2010 Location: San Diego Co. Posts: 1,157	Re: 12 bolt ID subscribed

09-27-2011, 02:56 PM	#7
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: 12 bolt ID Interesting, done brushing, cleaning and found this: on R/H upper side of Tube: RHC W144 2 Does this mean it's a posi 373? If so I'll be stoked..Interesting as the truck was a plain jane 71 6 Cyl truck with only two items on the spid: Red/white paint & Gage cluster. Didn't even have a Cig lighter just the delete plug in the dash. Whatever I got a good deal for a $50 bill. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

09-27-2011, 03:54 PM	#8
stomper Junior Member Join Date: Jul 2002 Location: Scottsdale, AZ Posts: 1,700	Re: 12 bolt ID Subscribed __________________ "I was patina when patina wasn't cool." 1973 Cheyenne SWB Sunset Gold / Frost White / Saddle

09-27-2011, 04:00 PM	#9
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: 12 bolt ID I looked all over the place on the www didn't find the codes listed by LONGBED67. Plenty of other stuff just nothing corresponding to my codes (RHC). Jacking one side up attempting to spin a wheel is a no go. I will assume it's a posi. Will know more once the cover comes off for fluid change. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

09-27-2011, 04:13 PM	#10
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: 12 bolt ID My book shows RHC as a 1972 3.73:1 ratio. The 1971 ratios all start with the letter "T". __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

09-27-2011, 09:59 PM	#11
longbed67 Registered User Join Date: Jun 2011 Location: Monroe, WI Posts: 1,415	Re: 12 bolt ID Yes should be a 3.73 posi unless someone changed the guts

09-28-2011, 12:47 PM	#12
stomper Junior Member Join Date: Jul 2002 Location: Scottsdale, AZ Posts: 1,700	Re: 12 bolt ID How does one decode the stamping after after the ratio code? I assume that's the date? I have one stamped "HC" (with an E) below it and what looks like "1027K" after. 3.73 posi is still in it and was told it's a '68. It's narrow. I have a pic but can't post from my Droid. Posted via Mobile Device __________________ "I was patina when patina wasn't cool." 1973 Cheyenne SWB Sunset Gold / Frost White / Saddle

09-28-2011, 01:15 PM	#13
stomper Junior Member Join Date: Jul 2002 Location: Scottsdale, AZ Posts: 1,700	Re: 12 bolt ID Pic. Sammy, Hope it's Ok if I kind of hyjack this thread. I can confirm another HC coded 3.73 posi. I reread posts closer and see Longbed67 already told us how to decode the month and day. Looks like I have an October, 27th built rear but what's the year? Does the "K" indicate that somehow? ..and Sammy's "W144 2" doesn't seem to compute. Attached Images __________________ "I was patina when patina wasn't cool." 1973 Cheyenne SWB Sunset Gold / Frost White / Saddle

09-30-2011, 01:35 PM	#14
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: 12 bolt ID From another site I gathered W was a plant manufactures code 1 was last digit of the year and 44 th day of production and 2 as 2nd shift. But who knows. Most important for me was the gear ratio..and the year of 71 which I knew as I removed it. Your "K" doesn't make any since to me at the end..My W is in the front..unless they just put them anywhere to indicate the plant assy point. Hijacking threads are a great way to learn stuff...from each other..so drive on and keep truckin.. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629" Last edited by Sammy; 09-30-2011 at 01:41 PM.

10-03-2012, 02:39 AM	#15
VA72C10 VA72C10 Join Date: Mar 2008 Location: Midlothian, VA Posts: 25,269	Re: 12 bolt ID Old thread....but What about HE1 11w Or TDA? Two different axles I have that I can't find the codes listed anywhere... Posted via Mobile Device __________________ Looking for a 67-72 swb or blazer project in or around VA.



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10-03-2012, 06:22 AM	#16
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,107	Re: 12 bolt ID subscribed Posted via Mobile Device __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

10-03-2012, 08:03 AM	#17
jjzepplin Registered User Join Date: Feb 2012 Location: Ruskin Florida Posts: 4,556	Re: 12 bolt ID Got two I need to decode to see which I will keep. One is def posi unsure of other. Can you tell ratio from stampings on ring gear? I seem to recall the guy I bought my 14 bolt from pulled the cover and showed me the 4.10 stamp. __________________ 70 swb 4x4 406sbc 700r4 203/205 d60/14blt locker yadda yadda http://67-72chevytrucks.com/vboard/s...88#post6935688 Yeller 72 Blazer 2wd conversion project "No Daggum Money" http://67-72chevytrucks.com/vboard/s...d.php?t=550804 LS1-T56 3.73 LSD super budget build Blanco-2014 Sierra SWB https://67-72chevytrucks.com/vboard/...d.php?t=810350

04-07-2013, 11:47 AM	#18
mechanic58 Registered User Join Date: Oct 2012 Location: Bremond, TX Posts: 32	Re: 12 bolt ID Man - I have been searching all over the internet for information about these stamp codes and I just can't find anything. I am looking at an axle from a '65 Chevy pickup that is stamped "WE327" on the tube. I can't find ANY information on that particular code. I want to find out the gear ratio. The axle is fairly far from me or I'd just go take the cover off and find out.

05-25-2016, 10:40 AM	#19
Boatracer Registered User Join Date: May 2016 Location: Olalla, WA Posts: 31	Re: 12 bolt ID Also looking for axle code "TDA"

05-25-2016, 10:49 AM	#21
Boatracer Registered User Join Date: May 2016 Location: Olalla, WA Posts: 31	Re: 12 bolt ID Thank you!

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