Need Help on Fluid choice

POSI? Thats a 4 letter Chevy term. :rofl: Anyway, I remember having ATF in my 74 360 Duster 833, & I'm pretty sure it came from the factory that way.

Not sure the old gears and bearings were tight enough for ATF, but it would certainly shift a lot easier in colder weather and it will be a lot noisier.

I looked @ brewers' site and they recommend Brewers recommends
GL4SL ONE GALLON STA-LUBE 85W-90 WEIGHT GEAR OIL
Get a gallon jug and you have all you need. You can get it at Napa and Walmart.