1954 Cast Iron Power Glide: Over-fill concerns

[retro54]

I have a 1954 Bel Air with the cast iron powergluide that was fully rebuilt 19 years ago.  I've owned the car 21 years, but last Saturday, over filled the cast iron powerglide automatic transmission for the first time. The fluid came out of the fill-tube. I realized what I had done after dumping in my 1/2 to 3/4 of a quart. I am hoping that a powerglide expert could guide me on what to do.  I took it for a very brief drive (less than 1 mile) and heard some noise which i think may have been what is described as torque converter cavitation.  I dunno. Never heard the sound so came back home right away.  Was thinking if draining fluid and then refilling with proper quantity.  And then trying to drive.  Anyone out there know the ins and outs of this and can offer suggestions? 

 

If you have never been around a cast iron PG, please refrain from responding. (not trying to be rude, but I really am trying to avoid being mislead by an 'expert' who isn't familiar with this first-generation GM automatic transmission.  Not looking for guesses.)

 

Thank you. 

Edited November 12, 2020 by retro54
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[Dave39MD]

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