I'm trying to get my Dad's 1956 Imperial roadworthy again, and one issue i'm having right now is what type of automatic transmission fluid to use. The service manual calls for 'Type A'. Hah! Try and find that.

I'm seeing that some guys are using Dexron 3 or Dexron 6 as a replacement, but opinions are all over the place. Is it safe to mix synthetic with conventional?

The transmission is the two-speed, pushbutton automatic (Powerflite?)

What say you?