Lol.
No, not GFCI. Fairly old construction. Per above, I don't imagine that a weak breaker would be an immediate trip. Especially when I see the same thing where I choose "air fluff" and so the heater element isn't even being energized. Something's drawing way too much current, and I'm thinking it's gotta be the motor.
The situation you described is very unusual.
For one thing, the heating element typically draws a LOT more juice than the motor so if it was a weak breaker it would still almost certainly work on the no-heat air fluff setting.
The motor itself should hit it's maximum draw when starting up*. Thus, if the motor was going to pop the breaker it would ordinarily do it on start-up, not a couple seconds later.
Dryer motors are usually 120v but the heating element is 240v so the motor itself is only using one half of the circuit.
Replacing the breaker isn't terribly difficult, you should be able to get one at any HD/Lowes, and that would save you some time diagnostically because you could at least rule that out.
*Example:
I've run into a situation multiple times where the kitchen breaker will trip if the refrigerator kicks on while the toaster or toaster oven is on. However, if you start up the toaster while the refrigerator is already running, no problem. The situation is basically this:
- Toaster draws 1,200 Watts. At 120V that is 10 Amps (Amps*Volts=Watts).
- Refrigerator draws 480 Watts running but 720 Watts on start-up. At 120V that is 4/6 Amps.
- The combined draw is thus 14 Amps when the Refrigerator is running and 16 Amps when the refrigerator starts up.
- If this is a 15 Amp breaker (cheaper because you can use smaller, 14 GA wire instead of larger 12 GA wire) then it will trip if the refrigerator kicks on while the toaster is on but NOT if you start the toaster after the refrigerator starts.