when does an automatic transmission shift?
When accelerating gently, first gear goes from 1,500 to 2,000 rpm, and the car reaches some 10 mph, then it shifts in second gear, which starts at 1,500 rpm and goes to 2,500 rpm, and the car goes to 25 mph and so on. This mild acceleration will get the car into fifth gear at relatively low speeds, say 45 mph.