Author Topic: 67 Dearborn Differential 3rd member date codes  (Read 1018 times)

Offline brennancarey

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67 Dearborn Differential 3rd member date codes
« on: July 16, 2019, 03:57:40 PM »
Hi

I am busy trying to find dated coded parts for my Dearborn 390 Build Date 12/28/66

Carrier Housing I have found is 6K25. Would this be an accepted date range ?

Pinion Retainer I have  is confusing me as it looks like its dated 11 .. 6.  Any ideas about this and if its correct ?

Thks  ;D

67 GTA 390 Fastback
Dark Moss Green
Dearborn
Build Date 12/28/66

Offline J_Speegle

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #1 on: July 16, 2019, 06:02:59 PM »
I am busy trying to find dated coded parts for my Dearborn 390 Build Date 12/28/66

Carrier Housing I have found is 6K25. Would this be an accepted date range ?

IMHO and looking at other examples - yes.

As for the pinion retainer it appears that its a reverse pattern from the way we see some (year - month day of month) to the Day of Month - Month - Year. This may suggest that it is from a different time period changed out when the rearend was rebuilt or disassembled as it appears to have been.



If so then the month has possibly two "legs" suggesting the possibility of M or H. The two legs may also be two dots suggesting a later period than the mid 60's

Don't have as many pinion date pictures as I do the main case ones


Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline brennancarey

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #2 on: July 17, 2019, 02:17:49 PM »

As for the pinion retainer it appears that its a reverse pattern from the way we see some (year - month day of month) to the Day of Month - Month - Year. This may suggest that it is from a different time period changed out when the rearend was rebuilt or disassembled as it appears to have been.

If so then the month has possibly two "legs" suggesting the possibility of M or H. The two legs may also be two dots suggesting a later period than the mid 60's

Don't have as many pinion date pictures as I do the main case ones

Ok great thanks for the info Jeff..  Do you think that the pinion retainer date code could be reverse pattern ,  11H6, 11K6 ?  If thats a possibility that would be :
 
66 Aug 11
66 Oct 11

If so those would both be dates that are in the correct date range based  for the carrier. thoughts?

May I ask what are the signs that indicate  your comments. : "This may suggest that it is from a different time period changed out when the rearend was rebuilt or disassembled as it appears to have been. "  ?

thks !
67 GTA 390 Fastback
Dark Moss Green
Dearborn
Build Date 12/28/66

Offline J_Speegle

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #3 on: July 19, 2019, 05:36:45 PM »
Ok great thanks for the info Jeff..  Do you think that the pinion retainer date code could be reverse pattern ,  11H6, 11K6 ?  If thats a possibility that would be :
 
66 Aug 11
66 Oct 11

If so those would both be dates that are in the correct date range based  for the carrier. thoughts?

Could be a reverse pattern and that may suggest or confirm that its from a different decade. Not saying that it applies in this case but its not unusual for guys to sell cast items made in 78 or 88 as 68 parts ( just as an example) especially like rearend carriers and such, since the dating pattern does not give us anymore than the last digit of the shortened year. I don't have any records or pictures of a reverse pattern in my collection - just saying




May I ask what are the signs that indicate  your comments. : "This may suggest that it is from a different time period changed out when the rearend was rebuilt or disassembled as it appears to have been. "  ?

The red oxide ring shown to the left in your picture. But I don't do rearend rebuilds on a regular basis I recall seeing those but not on this period of time. Sure someone else is more familiar with that specific design and application
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline preaction

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #4 on: July 19, 2019, 06:29:53 PM »
Jeff, do you have idea how to read the circular 1,3,5,7,9 and is the raised dot part of it ?
8F02R218047-  July 18 1968   Dearborn

Offline brennancarey

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #5 on: August 17, 2019, 09:59:25 AM »
Hi

I am busy painting and detailing my 9"  3rd member parts for my 67 S code . I am a bit confused about how to detail the pinion retainer as mine looks a bit different to the references I see here on the forum.  :o

As I am understating it, the machined surfaces need to be bare metal but on my pinion retainer there are no machined surfaces the entire thing has the rough cast finish so looks like these surfaces were never machined. So what do I do...  Any ideas suggestions would be appreciated.

Thks



« Last Edit: August 17, 2019, 10:02:41 AM by brennancarey »
67 GTA 390 Fastback
Dark Moss Green
Dearborn
Build Date 12/28/66

Offline J_Speegle

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #6 on: August 17, 2019, 04:27:13 PM »
As I am understating it, the machined surfaces need to be bare metal but on my pinion retainer there are no machined surfaces the entire thing has the rough cast finish so looks like these surfaces were never machined. So what do I do...  Any ideas suggestions would be appreciated.

Considering our focus here I would suggest finding the right one for your application rather than the 70's version

Notice the date and the D2SW casting

Believe that would be easier than trying to add the machined surfaces to the one you have
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline brennancarey

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #7 on: August 17, 2019, 05:08:49 PM »
Hi sorry Jeff, excuse my ignorance but I understood the date code was 6K11 ie 66 ? (and that is was stamped backwards)

what does the D2SW signify ?
67 GTA 390 Fastback
Dark Moss Green
Dearborn
Build Date 12/28/66

Offline J_Speegle

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #8 on: August 17, 2019, 05:43:50 PM »
Hi sorry Jeff, excuse my ignorance but I understood the date code was 6K11 ie 66 ? (and that is was stamped backwards)

what does the D2SW signify ?

Don't look at it that way - we're all here to learn

Engineering number D2 should indicate a part designed or redesigned in 72 so parts after that part (often for years) would carry that identification until a revision was needed. A date code of 6K11 with the D2 would suggest a part cast in Oct 11th 1976

Hope this helps
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline brennancarey

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Re: 67 Dearborn Differential 3rd member date codes
« Reply #9 on: August 19, 2019, 05:47:42 PM »
Thank you Jeff for the explanation, I guess the hunt continues..
67 GTA 390 Fastback
Dark Moss Green
Dearborn
Build Date 12/28/66