There’s a few articles out there. A search on Google scholar might show some more results but I just clicked one of the first ones for, “automatic vs manual transmission efficiency”
To the driver, a continuously variable transmission (CVT) operates a lot like an automatic. You don’t have to operate a clutch, and you simply put the car in drive to go. Unlike manuals and automatics, however, CVTs have infinite combinations of gear ratios. What that means is that a CVT can always send power to the wheels from the engine in the most fuel-efficient way possible.
There’s a few articles out there. A search on Google scholar might show some more results but I just clicked one of the first ones for, “automatic vs manual transmission efficiency”
At least based on fuel efficiency, an up to date automatic will be more fuel efficient. A manual will always be more fun and have a place in my heart.