I cannot find my axle code - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Rick Bollinger · 11-01-2018, 07:21 PM

I have looked for my axle code everywhere but need some help with ID.

Axle stamp says HB 0509
Casting stamps 67880 and 12345
12 bolt 1968 C 10

Looking for what ratio is and open or limited carrier without pulling cover off.
Thanks
Rick

B. W. · 11-01-2018, 09:06 PM

I know you don't want to hear it, but the best way to check your ratio is to pull your cover. It's 50 years old & may have been changed at some time & it never hurts to service the diff.

If I'm right HB = 3.07 ratio (but I could be wrong!)

Bones72Super · 11-01-2018, 09:35 PM

If the fill plug is recessed on the housing then it is an open carrier.If the fill plug is protruding from the housing it is a posi/limited slip.If the SPID is still in your glove box and rear end ratio is not noted it should be 3:08

hope this helps

Rick Bollinger · 11-01-2018, 09:55 PM

Thanks for the info. I thought it was a 3:08-3:07 but wasn't sure. But when I did my dash tach it says that at 60 MPH I am at about 26-2700 RPM. I have a TH-400 with 31/10.5/15 tires. With this combo that seems like a lot of RPM's. I am going to pull the cover this weekend to verify. My tach may be off.
Rick

geezer#99 · 11-01-2018, 10:13 PM

Might be tach.
You should show a little over 2000 rpm.

http://www.advanced-ev.com/Calculato...Size/?speed=70

**LockDoc** · 11-01-2018, 10:36 PM

Quote:

Originally Posted by Rick Bollinger

I have looked for my axle code everywhere but need some help with ID.

Axle stamp says HB 0509
Casting stamps 67880 and 12345
12 bolt 1968 C 10

Looking for what ratio is and open or limited carrier without pulling cover off.
Thanks
Rick

B. W. is correct. HB is '67, '68, & '69 3.07.

LockDoc

Rick Bollinger · 11-01-2018, 10:38 PM

Thanks Geezer
That's exactly what I need. Calculator says close to 4:10 with my set-up and a fairly healthy 350 on a hot day I can hardly spin a tire on asphalt. But it will cruise all day at 75 mph so I am leaning toward 3:08's and tach off.

Thanks

Rick

11-01-2018, 07:21 PM	#1
Rick Bollinger Registered User Join Date: Mar 2018 Location: Colchester IL Posts: 297	I cannot find my axle code I have looked for my axle code everywhere but need some help with ID. Axle stamp says HB 0509 Casting stamps 67880 and 12345 12 bolt 1968 C 10 Looking for what ratio is and open or limited carrier without pulling cover off. Thanks Rick

11-01-2018, 09:06 PM	#2
B. W. Registered User Join Date: Nov 2014 Location: Bigfork, Montana Posts: 1,137	Re: I cannot find my axle code I know you don't want to hear it, but the best way to check your ratio is to pull your cover. It's 50 years old & may have been changed at some time & it never hurts to service the diff. If I'm right HB = 3.07 ratio (but I could be wrong!)

11-01-2018, 09:35 PM	#3
Bones72Super Registered User Join Date: Sep 2017 Location: Lake Travis,Texas Posts: 769	Re: I cannot find my axle code If the fill plug is recessed on the housing then it is an open carrier.If the fill plug is protruding from the housing it is a posi/limited slip.If the SPID is still in your glove box and rear end ratio is not noted it should be 3:08 hope this helps __________________ WTB 71-72 Original paint Medium Red hood WTB 1972 Very nice original Parchment seat belt set

11-01-2018, 09:55 PM	#4
Rick Bollinger Registered User Join Date: Mar 2018 Location: Colchester IL Posts: 297	Re: I cannot find my axle code Thanks for the info. I thought it was a 3:08-3:07 but wasn't sure. But when I did my dash tach it says that at 60 MPH I am at about 26-2700 RPM. I have a TH-400 with 31/10.5/15 tires. With this combo that seems like a lot of RPM's. I am going to pull the cover this weekend to verify. My tach may be off. Rick

11-01-2018, 10:13 PM	#5
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,706	Re: I cannot find my axle code Might be tach. You should show a little over 2000 rpm. http://www.advanced-ev.com/Calculato...Size/?speed=70

11-01-2018, 10:38 PM	#7
Rick Bollinger Registered User Join Date: Mar 2018 Location: Colchester IL Posts: 297	Re: I cannot find my axle code Thanks Geezer That's exactly what I need. Calculator says close to 4:10 with my set-up and a fairly healthy 350 on a hot day I can hardly spin a tire on asphalt. But it will cruise all day at 75 mph so I am leaning toward 3:08's and tach off. Thanks Rick



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