american bulldog/mastiff mixed

Question
I have a spade 9 month old american bulldog/mastiff mix. She (molly) is scared of all loud noises (trucks, horns, doors closing ect ect) We have a big yard that is fenced in and it's kind of busy street. So everytime she hears a truck she tries to go back in side. She barks at everyone that comes over to the house. Took her 1 week to get use to my mom. She barked at her everytime she moved but if we are out in public and the person does not have a dog with them she will be scared of them but won't bark of them. When i walk her she walks with her tail down. Help.

Answer
This dog needed to be in obedience classes 6 months ago. I strongly suggest you get her into one now before this gets to be a situation where someone gets hurt.  Fear is worse than aggression in a dog because you can't predict it.

At this point in time, it's really going to take some effort on your part to turn her into a socially well adjusted dog. Socialization should be done before 4 months for the best benefit, but it's not too late.