My independent mechanic says it typically drives him nuts to have customers breathing down his neck while he's working, bothering him by asking questions all the time.
However, I bought he and his wife dinner last year on his birthday (Pappadeaux) and now I'm invited to hang around and ask all the questions I like. In fact, he will often tell me to get under the car and see what he's doing if I'm not already under there.
Of course, we're in his residential garage and he doesn't have liability insurance for his moonlighting work for which he only accepts cash... but I learn a lot every time I have something repaired.
See if you can find a good shadetree mechanic and buy he and his wife dinner. That'll get you right under there with him
