I bought a 1982 GMC S-15 truck, new. It had a really annoying squeak in it that apparently only I could hear. My wife and friends all said they didn’t hear it. Four visits to the dealership produced no results. I was starting to doubt my sanity and think it was an auditory hallucination, probably caused by a tumor. One afternoon, I was taking my Australian Shepherd dog, Dora to the park. Dora always rode in the passengers seat. As I went over a bump, the squeak occurred. Dora looked at the passenger footwell, then looked at me, then back at the passenger footwell, plainly indicating she had heard a noise there that didn’t sound right. I could have kissed her. I took it back to the dealership the next day, and insisted the youngest mechanic there (who wold have the highest frequency response in his hearing) ride around with me for an hour until I got it to occur again. It finally got fixed...