alternator advice 2002 Yukon XL 1500 SLT

[cruiser1]

New guy, just got out of the truck and heard this high whining sound that eventually goes away as it warms up.

Truck has 303,563 so far and I hope to go at least 500,000.

I'm guessing alternator as I feel a grinding when I touch it as it makes the noise.

Original engine and most parts. Trans at 165,000 nothing else major

 

[txab]

If that's where the sound is coming from, replace it now. Rockauto is one place to look as well as a local NAPA