Car makes this sqeeking sound when statring up could it be the alternator

tighten the belt, its too loose

you probbley need a new belt tensioner. the springs in it heat and cool and get weak..Hope this help you???

Try putting a new belt on, maybe better brand of belt, they do make belt stop sqeek but its not worth buying. Belts can make noise when cold, check to see if maybe your belt skipped a notch.

take your pads back off take the backing plate off load a bunch of anti sqeek between the pad and plate then the plate and caliper should solve your problem unless its your coposition off your pads some grades of semi metallic pads just sqeek.

correct belt tennsion is key in this issue if the belt is too tight it will put too much pressure on the alternator drive shaft thus exessive wear on the bearing and then jamming which will burn through your fan belt.

on most cars a recommeded 3cm or 1" movement (or play) shold be in the belt unless you car has an auto tension fillted.

IF THIS noise IS COMING FROM a WHEEL IT IS BRAKE PADS OR SHOES, If it is Coming from the TRANSMISSION It NEEDS to GO to A TRANS SHOP or Dealership as it would be an INTERNAL Fault.
Hope this Points you to the Problem !

make sure its tight and make sure you replaced all the belts unless its serpentine. I would try some belt applicator aka belt spray

sounds like u need a new belt may be dry rotted or just worn but also look at your belt pullies

sounds like you have oil on the belt.Or its lose.

It could be that you got some water on your serpentine belt and that will cause it to squeak. Try buying a can of "belt dressing" from an auto store and spray it all over your belt and see if that will stop it. It's a cheap and easy thing to try before replacing expensive parts. Hope this works for you, let me know how it goes. Goodluck!