i have a 95 auto /w 53k miles

this started happening after igot my alpine installed.

sometimes when the tranny downshifts and the rpms get around 3-4.5k theres this whining sound i hear. kind of like a high psi turbo.. just not as loud. any clue as to what it is?

 

Bad ground on the head unit.

 

any damage being done?

 

No, just tighten the ground wire on the head unit down, or move it somewhere that has better metal-metal contact.