Almost 3 yrs old ... possibly showing signs of Auditory Defensiveness?

I'm reading this checklist because my daughter who is almost three has extreme fears of specific things; IE: hairdryer, public bathrooms (because of the loud flushing toilets or automatic hand dryers), tractor, vacuum, hand mixer, drills. Pretty much anything that looks mechanical and may have a plug will make her nervous. If taken off guard by them, she will erupt into tears. Some times even shaking she is so scared.

She is very social, interactive, and enjoys playing with other kids. We try not to startle her with any of the above things mentioned. If we are going to use any of them, we forewarn her. She will often go to her room, close the door and put on music (loudly!) or cover herself in her favorite blanket. She sucks her thumb, and sometimes I have caught her rubbing the corner of her blanket on her ear. Other than that, she is a perfectly behaved, well mannered, good natured little girl who always seems to be smiling.

I'm concerned because she does have problems with some of her speech (she still can not pronounce some letters) and I am not sure if it is normal or not. Any ideas if this sounds normal or if she may need to be evaluated for a SPD?