What about if you are in a town centre waiting to cross at some traffic lights, with trucks using their air brakes?

I have never really taken him into the busy town parts as they are not too dog friendly. BUT as soon as I saw what you said there I feel like he could probably do to be desensitised. Perhaps I could take him on a walk that goes nearer these areas?

Usually if we are waiting to cross the road and there are loud vehicles around (like the bus stop next to the park, those buses hiss a lot) he pays little attention.

Sorry if I am not being very helpful or whittering too much! I am thankful for your help c:

If I don't reply for a while, its because I am popping to the park with the dogs.

I live in the countryside and have to go out of my way to go into town to socialise my puppy. It's not a particularly fun walk but it's important to me that she is bombproof with traffic. I wait to cross at traffic lights and sit at bus stops so she thinks nothing about air brakes at all.

I think my Clix noise CD has truck noise on it too. I know you said you played a CD, did you play it very loudly in different rooms?

I think you've been given some great advice already and hope something works for your little guy with the dustman's air brakes.

I'd be inclined to always be outside, out the back, playing with him, keeping him occupied when you know they're coming.

I have a great fear of spiders, I run a mile if I see one indoors, shake like a leaf etc. etc. BUT when I see them outside, it has little effect on me, all very strange, but from what you are saying about your dog it seems he is the same with the hissing sound of those brakes, so it makes sense to have him outside when you know they are going to be around. good luck with it all, and a den of some kind sounds fab too!