[RamAirBirds]

I had started a thread the a couple weeks back on The YENKO Forums pertaining to the correct color of the 67-69 Firebird Axle Colors. This thread is "69 F Body Rear Axle Color *Latest Consensus*"
With some great response it is easy to conclude that PONTIAC axles in that time period were shipped from PONTIAC and were bare steel and were hit with overspray of black after install into car. See the photos on that thread. So the proper restoration is Cast Gray center section and natural steel tubes and backing plates with the overspray of black.
It was also concluded that all CHEVROLET axle ship from a different axle plant and were always painted ALL BLACK. Everything except the yoke and the wheel studs.So the question is that since all 1970 Trans Ams along with 71-72 GTOs with the 455HO had CHEVROLET 12-Bolts installed it should be easy to assume that these axles were also painted ALL Black just as the Chevrolet Counter parts were. I inquire as I have been restoring a 70 RAIV TA for some time now and currently have the 12-bolt axle painted in the way you would a 67-69 Firebird or GTO i.e. Cast Gray and Natural Steel. I am thinking this is incorrect and should be ALL BLACK based on the evidence as shown on the previously mentioned thread. I know there are some TA experts out there on this forum and would love to have comments / thoughts. Pretty Sure I am correct in the fact that ANY 12-Bolt Axle installed in a 70 Trans Am or 71-72 455HO GTO would be ALL BLACK.
Thanks to everyone who chimes in.
RA

[jhein]

The Yenko thread link isn't working.

[Ramairnacho]

Im.no expert and was planning on getting my 12 bolt powder coated black but was told that black.was incorrect color and natural gray was correct. Very interesting question. My car is a formula but I imagine it would be painted the same on all cars. 12 bolts came in esprit,formula and trans am. The Norwood car was an orange red color and if there was over spray it would easily be seen. I'll look under mine and let you know.

[RamAirBirds]

The Esprit would not get a 12-Bolt. Only the Formula and TA.
We will see what people say here but I am fairly confident with the info gathered that 70 Trans Am with 12-Bolt will for sure be all black.
I have the original unrestored 70 TA that came out of California (Sold New in New Orleans) that was on BAT over the summer. I am going to go take a look at that when i can make my way to where its at. Crazy I forgot i had the car as this subject was coming up. I just attached some photo of the Mark Bulaw Unrestored 70 TA and the ne photos looks all black. Tubes im not sure if he cleaned to see codes. The one looks like it may be a closeup of his driveshaft showing paint stripes.
I am sure many people painted natural steel tube / cast center as that was the norm on a PONTIAC axle. I did this on a 70 I am restoring. I am feeling i am going to have to make that correction..

[RamAirBirds]

on second look after I uploaded I am fairly certain the last 2 photos are of the driveshaft. Take a look mainly at photo #1. Looks all black.

['ol Pinion head]

Factory 1970 400 2bbl Esprits received 12 bolts. Have pulled several over the years.

['ol Pinion head]

When get a chance in a week or two will take a closer look at the June '70 stamped COZ T/A rear I have in one of my housing racks. Have had that very clean core rear for many years. Of the more common application '70 F-body usage 12 bolt rears, have had quite a few clean ones, but most were just COS & COT coded 3.07's. Most I've built them up with aftermarket gears, new axles, & rebuilt Eaton posi carriers. One COS coded 12 bolt I have, decades ago i strapped it under the front of the frame of a '70 GTO body on frame. had no upper & lower control arms & disc setup removed. Made for a quick way to make the partial project a roller. After several years setting outside on the concrete, i removed that particular 12 bolt from under the front frane. The axle tubes & housing were just surface rusty, if it had any black paint on it, it was super thin to begin with.

On McKinnon mfg original Olds, Buick, & Pontiac usage 12 bolts, I've confirmed both factory painted & unpainted original housings. McKinnon did quite a few things differently on the 12 bolts they built for non Chevy usage, i.e, in our interest, '70-72 Pontiac A/G usage. Differently, as in not just different coded housings, but different style backing plates, different drums, different factory axles, & of course a 3R pinion flange to directly bolt up. Last there were no silly color band stickers wrapoed around the the axle tubes to quickly ID the ratio of rearend at the assembly plant. Instead, a two letter code was painted with a stencil at the McKinnon plant on the face of the drivers side installed brake drum. Am not sure it's wise to categorize the McKinnon 12 bolt built rears in with the much more common 12 bolt c-clip axle rears being built out of, say, the Bufflalo axle plant.

[Ramairnacho]

Not sure if it wads ever painted but it's a 12 bolt cos. My parts car is not a fancy car but it's all original. I might make it live again. Hope I could help.

[Ramairnacho]

Not sure if it wads ever painted but it's a 12 bolt cos. My parts car is not a fancy car but it's all original. I might make it live again. Hope I could help. If you look closely you do see black paint. I really like this group and I'm learning. I will probably have rebuilt posi 307 or 331 and powder coat black or por 15 and primer epoxy and black..

[Formulabruce]

Originally Posted by RamAirBirds

The Esprit would not get a 12-Bolt. Only the Formula and TA.
We will see what people say here but I am fairly confident with the info gathered that 70 Trans Am with 12-Bolt will for sure be all black.
I have the original unrestored 70 TA that came out of California (Sold New in New Orleans) that was on BAT over the summer. I am going to go take a look at that when i can make my way to where its at. Crazy I forgot i had the car as this subject was coming up. I just attached some photo of the Mark Bulaw Unrestored 70 TA and the ne photos looks all black. Tubes im not sure if he cleaned to see codes. The one looks like it may be a closeup of his driveshaft showing paint stripes.
I am sure many people painted natural steel tube / cast center as that was the norm on a PONTIAC axle. I did this on a 70 I am restoring. I am feeling i am going to have to make that correction..

There were a Bunch of ESPRIT 400 Firebirds made WITH a 12 Bolt. ( this is NOT speculation fyi) Most were open, but a Safe-t-trac could be ordered.
The rear ends were Bare steel from the factory ( we will call this day "Zero" )
Day 1 ( at the dealership) when these cars were set up the set up tech ( I was one in the later 70's at a Pontiac dealership) had a checklist of items to grease, and check, And had Black paint to apply to any rusty area that could be seen from the side ( wheel arched inside) Or from the rear of the car, or front for that matter. Many of these cars, depending on where it was shipped got surface rust and the set up tech sprayed them haphazardly on the bottoms, back of axle only, or anything including backing plates.
Last yeah I rebuilt a couple, one was covered in greasy grime because it had a pin hole in the tube spot weld that leaked. both sides. This covered most of the rear with grease/dirt/gear oil. Once I just cleaned it with a brush and dishsoap it looked like brand new INCLUDING the axle tube seam weld all the way to the end of the axle.
Have seen this on many 10 bolts as well, but most have a spattering on the bottom or rear side.

[Formulabruce]

My Buddies 12 bolt I rebuilt last year. Mess made from new when there was pin holes in the axle tube welds. This protected the original finish.

[Formulabruce]

Note the axle tube weld marks ... and lack of any paint, or PITS!!

[RamAirBirds]

Very Interesting. I know Matt has an original untouched Low Mileage 70 Esprit so I will assume he has the 12 bolt worth looking at.
I will make my way down to the at the New Orleans TA when the cold breaks.
Matt, you will need to shovel a path to your building. Best I can tell hes had about 11 feet of snow since start of winter.

[keith k]

No factory paint on the axle is consistent with what I found when I looked at a number of original cars back in the 90s before restoring my first '70 T/A.

[Baron Von Zeppelin]

Chrome plating is the way to go - drum to drum .
Happy New Year !

[turbo69bird]

Originally Posted by Baron Von Zeppelin

Chrome plating is the way to go - drum to drum .
Happy New Year !

Actually an HPC header coating might look an awful lot like the bare steel. Just the right luster .

[Ramairnacho]

Is correct like steel clear on tube and black pumkin?

[Trevor78]

Not black, bare cast iron.

[Formulabruce]

Originally Posted by Ramairnacho

Is correct like steel clear on tube and black pumkin?

Center is cast iron bare as in my pic from above.
I clear coat these with a durable 2x clear

[turbo69bird]

Originally Posted by Formulabruce

Center is cast iron bare as in my pic from above.
I clear coat these with a durable 2x clear

This is a great picture of what things look like bare, I’ve had this discussion w Ole pinion head for years now about the rears and how they were painted as well as w a few other.

I’ve always said the cast center section needed to be darker cast, tubes natural steel is tough to replicate and welds should have heat weld marks as I posted on yenko and another person posted a great example of that w air brush work also on yenko. This picture is ONe example I’m sure they differed.

I posted the assembly manual version of the painting process on yenko as well I’ll see if I can find it in. Files again but not everything was actually done per assembly manuals.
Notice the hardware in the upper control arm in that picture as well appears to be painted black. Assembly manual also suggests it woukd have been black from the way I interpretation it.