This morning my xj started kind of weak, but i didn't think anything of it. After work I tried to start it and it sounded like a dead battery and tried again, and it came to life. It sounds like there is a new whine/hum coming from somewhere in the pulley system, is there a chance this new noise is my alt, and can it go bad that quick? I am on my way to class in a few minutes if it starts, I have plenty of help at the school if I get stuck there.

I have a new battery, volts read fine when started, and runs flawless once started. I can only assume alternator, but seems the symptoms hit hard, and the whine/hum that is new could also be the alt. correct?

Thanks