It seems to happen on the decompression after hitting a bump, if that makes sense, and can be heard whether the roof is up or down.
Waa qasab in la shageeyo qofka dhiibay, waxaa ay dhici kartaa arrintan beri.Wxaan hubaa ama madax sare hala gasho ama madax hoose waa in la sheegaa hadduu sheegi waayo waxaa dhacaaya.