Need help with gear oil selection

ATF formulations have changed BIG time,in the last 10 years ago,much less 30 or 40. Ran into this a while back,as a parts guy. Seems air cooled V
W.'s required a GL4 ,just like the Mopars did. Sta-Lube,is the last true GL-4 brand left. The VW guy I know,says that only. The synthetics ,do have benefits. Brewer's, knows his stuff. Red line or Sta -Lube,would be my choices.