Talking with my neighbor about how folks dealt with car problems years ago, he related that a relative had a six cylinder Chevy with a particularly sluggish Powerglide.
Anyway, the remedy he used was to drain the old fluid completely, refill with half automatic transmission fluid, half brake fluid. Then he drove the car to get it to normal operating temperature then drained it again, refilling it with straight automatic transmission fluid. Apparently this gambit cured the problem and he drove the car for years afterward.
Anybody else heard of this old-time sluggish automatic transmission remedy?