VCCA Home Forums TECHNICAL - 1945 AND NEWER 1955-1957 56 Powerglide transmission color

Just to be on the safe side - a 1956 cast iron Powerglide - the correct "color" is simply "Cast Iron Gray" - right?

I realize the slight craziness of painting cast iron in order to simulate cast iron, but that's another topic.... the real mission after all, is to prevent the color from being "rust."

Just thought I'd ask and make sure I remember right, to save myself finding out later "Oh, no - in 1956 they painted them black," or something similar - don't want to deal with the possibility of painting it the wrong color and having to do it over -

The P.G. case was not painted. The external hardware, levers and rods, etc. was not painted either.

OK, thanks for that Gene. Now, what's the function of the hole, about one inch dia, right at the top in front? It's not threaded, nothing there. (I'm not talking about the plastic"Powerglide" badge, that's off to the side, and has a very small hole to snap into.)

I can't picture the hole from your description.

I always thought they were black, but its possibly the lighting of the assembly line shots that make them look black?

This is a B/W shot of a '56 drivetrain drop.




These assembly line shots are '59 Powerglides and 283s, but they seem to show a very dark cast iron matte finish. Looks black, I know.






I can see either way. If you do a natural finish, would you use a cast 'paint' to keep the finish preserved? I've cleaned and cleared transmissions before but they still seem to pop flash rust after a year or two :(

Hi, Daryl - it's a really tough call, eh? If we look at your top color photo, that's almost certainly gray, very hard to argue it is black. The second color photo, I'm like you - it sure looks black, but I could be convinced it's a dark gray fresh casting, the lighting, etc. The B&W from '56 - again, could be convinced either way.

I also posted this same question on Tri-Fives.com (the "stock forum"), which has a pretty huge audience. Getting split answers there, too. If there is a consensus, it would be that they were built "raw" and service or Parts Dept replacements were black-washed. I have a good friend, very knowledgeable, that is convinced they are painted black. But he has backed away a little to "black washed" as opposed to actual painting. And we also have to consider different procedures in different years. Nobody ever argued that my '53 should have been black, it was done in natural gray. And the photos from 1959 - who knows, did they change procedures?

I had always been of the opinion that they were raw cast iron. I know absolutely that there is NO TRACE of any black paint on my '56 - and there are lots of nooks and crannies there, where a dab of paint should have survived.

Yes, I use Bill Hirsch "Cast Iron Gray" paint. First I sandblast, scrub down with lacquer thinner, acid etch with Phosphoric acid, wait a day, scrub down again with steel wool and lacquer thinner, then spray.

When new the cast iron has a gloss finish. The only painted ones were rebuilts that some rebuilding companies painted.

Have no idea what the hole was for .... the "spare" I have in my garage does not have a hole.

The standard transmissions were not painted either.

If the P.G. is out I would suggest replacing the front pump seal and converter "cover" O ring as long as it is out. A common sorce of leakage.

Thanks - it's completely freshly rebuilt - clutches, bands, seals, etc.

The hole was for a plastic plug. The ones in the photos are far from rebuilt they are from the Tarrytown Factory (notice the rail car in the back round)
There are some other color photo's and the six cylinder powerglide was natural. It sure looks black to me....
It is not a glossy cast iron finish, in other photos the stamped steel dipstick tube is black also

By the way the hole is there to pop the converter forward to bolt to the flexplate, I had seen blue plastic plugs in the hole in all of the ones I took out but one. I came upon a green one and that was in a 305 HP 348, which was supposed to be a heavy duty unit.
If they were all natural from the factory then how come they never look that rusty, but the standard transmissions do?

As the Rolling Stones said, "Paint it...... Paint it black"
a factory photo over rides everything

All I can say is that they were unpainted and I was there at the time and saw many of them being worked on in the dealership.

So you are saying the photos are wrong then? Looks like there is a whole rack of them in the back round all painted black or covered with a black wash. Turboglides were natural, cast aluminum maybe you are mixing things up, after all of these years it is possible.

the photo below was sent to me from another site, showing a 1955-56 assembly line. The Powrglide is clearly not painted black here.

I don't know if I can say it is "clearly" not painted or painted from the black and white photo, There could have been some sort of spray on rust preventor. Which I tend to think there was. Based on the fact I never really saw one that was rusty after 60 or so years of sitting outside to the elements, as any bare cast iron would be. They were built in one plant and shipped all over the country in rail cars not exactly a sterile environment, so I don't buy into the sheane of fresh cast iron theory, they were far from fresh when the units arrived to the plants

i restored our 54, 55, 56, and 57 corvettes which had their original power glides. none were rusty(in spite of several living their lives in Penna. ) none were painted balck. but they did have a blackish appearance under all the grease and grime. i glass beaded the cases and then used a light coating of woodstove polish to give them a blackish appearance. mike

Hey Mike,
Hope all is well with you, was wondering (I am pretty sure I know the answer) those Vettes were all NCRS winners? What finish does the NCRS accept for the cast iron powerglides? All of the powerglides were made in the same plant so one would think things would have to be somewhat consistent.
I do like the woodstove polish idea

NCRS will deduct for black PG's, usually cast blast will pass. the wood stove finish on all 4 of our c-1's passed without comment from the judges. the 54 top flighted in bend organ in 1988 and we've since given it to our oldest daughter who is into cars. the 55 and 56 were sold to rick handpick. they were restored by me for eventual NCRS duntov award but i sold them to rick before they were ever judged in NCRS. they are just inside the entrance to the Hendrick personal museum. if u ever get a chance to view his collection, go for it.200 pristine corvettes under one roof.
the 57 vet is a 250 HP FI vet, one of about 100 built in 57 optioned as such. it got its Duntov award in about 2010. i recently bought a 57 air box corvette, one of 43 built by chevy. i got rid of the 61 vet(Farm Use in shoe polish on its doors). its the one we had at the springfield VCCA meet years ago. it was built on a totaled 92 ZR1. hope all well with u all. mike