CRG Discussion Forum
Camaro Research Group Discussion => Restoration => Topic started by: Mike S on December 29, 2017, 03:22:25 PM
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Here's a splitting hairs question....
For posi differentials....was the red triangular 'Use Positraction Diff Lubrication....." tag on the fill plug when the assembly was painted black? Or was it installed afterwards.
I assume if it was on the fill plug prior to painted that it would be masked somehow. And did the original tag have a slit on the end to slip over the plug neck.
Just curious,
Mike
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Mike, this would be a good question for John. I'll see if I can get him to reply.
In the meantime, here's what I believe.
The axle was painted at the axle assembly plant (i.e. the Detroit Gear and Axle plant), but not filled until it got to the vehicle assembly plant (Norwood or Van Nuys). This leads me to believe that some kind of plug or cover may have been used to cover the fill hole when the axle was painted, and then the plug and tag (which came as a "unit" - P/N 3866433 - see below) installed after the axle was filled.
Of course, this is just a guess on my part, but it seems to me that if the "unit" were painted at the axle plant, it would be difficult at best to completely mask off the tag and I don't recall ever seeing any overspray on any posi tags.
Ed
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Guys -
The axle left Detroit Gear & Axle with no lube, but with the 4-sided plug in the fill hole. On the Chassis Line at the car assembly plant, the plug was removed, the axle was filled (with Posi lube if it was a Posi, or with regular hypoid lube if it wasn't), and the plug was re-installed (with the red plastic Posi tag added if it was a Posi axle). The "unit" shown was a Service part for the dealers. :)
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Thanks Ed and John. And welcome back, John!
Happy New Year....
Mike
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John also said
“Yes, the plug was present when the axle was painted at Gear & Axle. The Posi tag was installed by the axle fill operator at the car assembly plant.”
From what I have seen (Bryon) the paint that was used was cheap and didn’t stay on very long on most cars. And I don’t remember seeing any tags that were split.
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Did the assembly-line posi tags have 'DIFF.' or 'DIFF'?
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Yes, what did the assembly line tags look like?
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Did the assembly-line posi tags have 'DIFF.' or 'DIFF'?
I asked this a few years back and it was DIFF.
http://www.camaros.org/forum/index.php?topic=10511.msg79784#msg79784
Mike
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Mine has the period
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I asked this a few years back and it was DIFF.
Mike,
Was it “DIFF.” for just ‘67 or was it that way for ‘68 and ‘69 as well?
Thanks,
Bob
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Our 68Z had the "Diff." with the period and if I remember correctly that is what the NCRS judging manual states.
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Hmmmmm....ALL of the Camaro vendors sell a ‘68 and up tag with a 3/4” hole that have “Diff” without the period. Paragon sells one with the period but the hole looks to be 1”.
https://www.paragoncorvette.com/p-359540-rear-differential-carrier-tag-posi-traction.aspx
Did the ‘68 and up tag use a 3/4” or 1” hole? Is this a case where the Camaro repro parts are yet again wrong?
Bob
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Yes, through late 1967 production the plug was 3/4 x 14 (Service P/N 3866433 - "Plug & Tag"), then starting late 1967 production (exact date unknown) and after, the plug was 1/2 x 14 (Service P/N 3931171 - "Plug & Tag").
Ed
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Thanks Ed.
So let me see if I understand this correctly....
1. All ‘67-‘69 tags should have the period after “DIFF” regardless of the diameter of the threaded portion of the plug.
2. The diameter being referred to by many of the repro suppliers is the diameter of the hole in the tag not the diameter of the threaded portion of the plug. For example HBC (http://www.heartbeatcitycamaro.com/store/category/11/212/Rear-Axle-Parts/)
3. The tag being sold by Paragon (https://www.paragoncorvette.com/p-359540-rear-differential-carrier-tag-posi-traction.aspx) has the period after “DIFF” but with the larger diameter tag hole which, for example, contradicts what the Camaro repro suppliers are advertising for the ‘68 and ‘69 tag. Did the Corvette use a different plug that would use the larger diameter tag hole? Will this tag work with the later 1/2” Camaro plug?
Sorry for the questions but I didn’t think a lousy period would cause me so much confusion.😁
Bob
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Original tag from our 67 Corvette has the period after DIFF.
(https://farm5.staticflickr.com/4727/39412558371_43fc946f62.jpg) (https://flic.kr/p/233KEut)
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Interesting about plug sizes!
The one I got from LI Corvettes (DIFF.) is 1" and fit the '67 plug.
Mike
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I would need to climb under my 69 Corvette and 68 Camaro to compare the tags (maybe later today), but the Corvette used the same 3866433 (3/4 14) plug and tag from 1965 through 1979. This was also used on the early to late 67 Camaro before it went to the 3931171 (1/2 14) plug and tag.
The tag hole diameter of the 3/4-14 plug (3866433) is probably one inch and the 1/2-14 plug (3931171) is probably 3/4". (To find the diameter of a pipe plug, add 1/4" to the stated thread size).
Ed
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Since we are talking about painting.... I am assuming the brake lines were also put on at Chevy Assembly so they were not painted either..(?)
What about the bracket that the rear brake block attaches to at the top of the housing?
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Original tag from our 67 Corvette has the period after DIFF.
(https://farm5.staticflickr.com/4727/39412558371_43fc946f62.jpg) (https://flic.kr/p/233KEut)
Chick, since you have the one from your '67 Corvette (same as '67 Camaro?) and the one on your '68/69 Z28... maybe you could get an opportunity at some point to photograph both (front and rear) together??
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Gary, OK the truth will come out! The 68Z when restoring I put on a new posi tag from Paragon as the 68 tag was gone. Reason I think is the original owner told me two times he put 4.88 gears in the car and before selling (trade-in) put the original 4.10 back in so somewhere in changes the tag was not put back on. The 69Z I have or had the original tag for that but it was beat up so that car got a new tag when restored also but I did look for it recently and did not find as I believe it was eventually trashed over the years. I will see if I have a picture of it as I studied what was correct prior to purchasing the one I did for the 68Z.
To the question on painting, the emergency brake cables were on when the rear was painted.
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Check,
I suspect they are missing on many 'otherwise-original' cars.. either broken or discarded perhaps the first time the rear end juice is checked... What was interesting to me from this discussion is that different sized pipe thread plugs were used from '67 to 68/9 Camaros and different than same year Corvettes. Especially if I understand correctly that the '67 Camaro used the larger 1" pipe thread, and the later year ('68/69) Camaros used a smaller one... Going to a smaller check/fill plug certainly doesn't help when trying to add juice to a rear.