Cleaning outside of TH350 case

[Boston14]

I need some ideas on how to clean my Turbo 350 transmission case.  I have read what I could find on the subject, but need more input.  The transmission is original to the car and had never been out until I removed it for restoration.  I blocked all the openings and pressure washed all the major grime and road dirt off of it. After 44 years, it was pretty filthy.  The case is still very dirty looking and stained. Some say that glass beading will clean it, but will leave the texture on the aluminum wrong.  One guy says to blast it with walnut shells. What did you guys with the top show cars do, or have done, to give your transmissions that just off the assembly line look? Any help will be greatly appreciated.

[169INDY]

I cleaned up my "CX" find trans using the following method;
Remove trans & FME openings. i.e. plug lines, cap cover & temp tailshaft yoke etc.
Soaked exterior with Simple Green & Castrol Purple stuff.
Hooked up my craftsman electric pressure washer to my Hot water Tank output via garden hose.
I jacked up the burner on the gas heater to boost the temperature.
I ran the washer and made a huge wet mess, rinse repeat. Various brushes & The heat helped loosen up some of the gunge.
This did not provide a satisfactory finish & I was going to have a local TRANS specialist moonlight the rebuild in his garage. So I had an option to take the disassemble trans case and part and put them in a Solvent tank and really clean the surface.

I have found the following product work well to refresh the skin of Alum components.
Eagle One Mag wheel cleaner & the PPG products.
Essentially the Eagle on & DX579 etch the skin to remove a sluff layer.
The  PPG DX501 is a conditioner alum brightener that give the alum that fresh finish.

[Boston14]

Thanks for the reply Indy.  Here are a few pictures of what is going on with my transmission.  First is a before picture, then I pressure washed it, and started soaking it with Purple Power. I have started scrubbing the left side with a brass bristle brush.  I need to scrub some more and then start on the right side. Progress is slow but sure.  Then I guess I etch the skin and then brighten it with the DX579 and DX501.   Right?

[169INDY]

Your Progress is good.
A few ideas. From My experience.
Stubborn stains can be worked localized with some Laq Thinner.
The Eagle One Mag Cleaner & PPG DX579 are acid based and are the cleaners that will dissolve a small layer & must be worked in and rinsed. They create a layer that MUST be mechanically agitated - removed with a Brass (preferred) or Stainless brush.
After thorough rinse and dry time you can spray on a diluted PPG DX501 and let stand for the time indicated per mfr instructions. It brightens the fresh cleaned alum SKIN.

I have done a few manifolds, distr, and one trans.

This is a poor mans DIY skin cleaning. It is not as good as the pro's but It gives a guy a chance to fluff stuff locally in the garage.

Test, test, test and adjust.

Try it out.

JIM (169INDY)