Differential stamping
#1
Burning Brakes
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Differential stamping
Trying to find the factory stamp on the rear diff that will identify date and ratio on a 69. I understand it is on the right side. Hoping to find an HT Mark. Can anyone point me in the right direction, or do any forum members have an example to show the location? Thanks.
#2
Burning Brakes
Trying to find the factory stamp on the rear diff that will identify date and ratio on a 69. I understand it is on the right side. Hoping to find an HT Mark. Can anyone point me in the right direction, or do any forum members have an example to show the location? Thanks.
Last edited by Stephen Irons; 01-16-2017 at 04:07 AM.
#3
Melting Slicks
Same on the 69', except there is no shield. It is on the bottom of the diff case right next to the plate securing the leaf spring. Usually full of oil and grease, may need to clean it good to read it.
Joe
Joe
#4
Melting Slicks
Not my car but check out post #4. Sorry but what does "HT Mark" mean?
https://www.corvetteforum.com/forums...ere-is-it.html
https://www.corvetteforum.com/forums...ere-is-it.html
#5
Team Owner
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Hi GD,
The stamped information on the carrier case flange typically consists of and indicates:
a digit…..shift the differential was assembled
2 68) or 3 (69) letters….. ratio code
digits….date the differential was assembled (month/day/year)
a letter…. plant at which the differential assembled (D…Dana, E…Eaton, etc.)
In addition, there is a date cast into the side of the carrier case and another cast into the rear cover.
Regards,
Alan
Case… A 4 1….. January 4, 1971
Cover…. L 23 0….December 23, 1970
The stamped information on the carrier case flange typically consists of and indicates:
a digit…..shift the differential was assembled
2 68) or 3 (69) letters….. ratio code
digits….date the differential was assembled (month/day/year)
a letter…. plant at which the differential assembled (D…Dana, E…Eaton, etc.)
In addition, there is a date cast into the side of the carrier case and another cast into the rear cover.
Regards,
Alan
Case… A 4 1….. January 4, 1971
Cover…. L 23 0….December 23, 1970
Last edited by Alan 71; 01-16-2017 at 11:25 AM.
#6
Melting Slicks
Here is a picture of the bottom of the differential case from a 69 where you will find the stamped information giving the ratio code and date of assembly. Cast dates of the pieces are located on the drivers side for the main case and the back cover cast date is on the passenger side as Alan has shown pictures of.
Going right to left:
The first digit is the shift number, in this case a #2.
The next digits are FA which stands for 370 ratio Heavy Duty
The next set of numbers are the date of assembly 1-14-69 (Jan 14, 1969)
The last digit is the plant, W, (Warren)
Going right to left:
The first digit is the shift number, in this case a #2.
The next digits are FA which stands for 370 ratio Heavy Duty
The next set of numbers are the date of assembly 1-14-69 (Jan 14, 1969)
The last digit is the plant, W, (Warren)
Last edited by ed427vette; 01-16-2017 at 10:40 AM.
#7
Burning Brakes
Here is a picture of the bottom of the differential case from a 69 where you will find the stamped information giving the ratio code and date of assembly. Cast dates of the pieces are located on the drivers side for the main case and the back cover cast date is on the passenger side as Alan has shown pictures of.
Going right to left:
The first digit is the shift number, in this case a #2.
The next digits are FA which stands for 370 ratio Heavy Duty
The next set of numbers are the date of assembly 1-14-69 (Jan 14, 1969)
The last digit is the plant, W, (Warren)
Going right to left:
The first digit is the shift number, in this case a #2.
The next digits are FA which stands for 370 ratio Heavy Duty
The next set of numbers are the date of assembly 1-14-69 (Jan 14, 1969)
The last digit is the plant, W, (Warren)
Last edited by Stephen Irons; 01-16-2017 at 12:08 PM.
#8
Burning Brakes
Thread Starter
Member Since: Jan 2017
Location: The Buckle of the Bible Belt. Joplin Mo
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Not my car but check out post #4. Sorry but what does "HT Mark" mean?
https://www.corvetteforum.com/forums...ere-is-it.html
https://www.corvetteforum.com/forums...ere-is-it.html
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Andy Tuttle (01-17-2017)
#9
Melting Slicks
No such mark or reference for any 69 rear ends that I'm aware of. I could be wrong but never heard of it. What you may be confusing it with and hoping to find is an HD rear end. This would be determined by the two letters stamped after the shift number. In the example I showed, the letters were FA which would be a 370 posi rear, (HD) Heavy Duty, made for the 427. Sometimes the HD rear could be found on the 350hp small block but I am not sure if they did it on purpose or just to move the assembly line along. I don't know enough about the assembly in that area to give accurate information only to say there are original 350hp cars out there with heavy duty rears that seem to be original to the car.
Last edited by ed427vette; 01-16-2017 at 05:30 PM.
#10
Instructor
Checking the two digit code against the linked chart will tell you assemby date, ratio, and whether or not it's a HD diff.
http://corvettec3.ca/axle.htm
Here's mine showing CAU ('70 used 3 digit codes) for the 3.36 HD axle built on April 10, 1970.
http://corvettec3.ca/axle.htm
Here's mine showing CAU ('70 used 3 digit codes) for the 3.36 HD axle built on April 10, 1970.