Ok, I got another alternator to replace the one in my car that had gone bad after about 4 months??? dont know why. But this new (reman) one is whining like a supercharger and has the same rythum (louder under acceleration). Not screeching the belts or anything. So it took it off because i wanted to test it and it passes 3 tries. And i watch my voltmeter and its kinda twitching between ill say 13.7-12.7 volts - ish. But this morning its been ok stayin above 13v. Ive heard the whining is bad and is a sign if it about to go out? is this true. I also think my gauge may be a little faulty or needs to be cleaned too?? Just not sure what the whining means

 

if the whine stops when the voltage regulator plug is
off,that indicates there is a shorted diode in the alty
Alternator will still work but it will be weak and will
get real hot,even with a light electrical load.