May be different for a 1965, but everything I could find on my 1951 said the transmission wasn't painted. But I painted my 3 speed with "cast iron" rattle can paint.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
The GM plant in Arlington, TX didn't paint them at all...at least not that I ever saw. In fact, a painted transmission was a dead giveaway it had been rebuilt. Different rebuilding shops around here used different colors so they'd know what they had done in case somebody came in with a problem and they had unique colors of paint. There were a few shades of blue, some used gray, none used black (too common and easy to mimic), one used sort of an orange/yellow...stuff like that.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Since they were never painted, just paint it "Cast Iron" gray, that will look the closest to non-painted the way it left the factory without issues of future rust!
The engine/bellhousing/water pump/manifolds were painted engine color after assembly.
May be different for a 1965, but everything I could find on my 1951 said the transmission wasn't painted. But I painted my 3 speed with "cast iron" rattle can paint.
I smoothed the casting and painted mine the same epoxy, base and clear as the engine. I put all ARP bolts on it. I made little spacer sleeves to hold the heads of the bolts up to paint under them. I know it's dumb. I know nobody will ever see it. It's a waste of time and money. Blah, blah, blah. I think it looks cool.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.