Hi, my alternator coupler pulley is going bad and it is causing chirping noise when the car is fully warm up. It only chirp if I am at a stop in D or R. Once I give it some gas, the chirp goes away. I found a video online where you don't need to remove the fan shroud or the radiator. Can anyone verify this is method is possible?

Videos

more likely the belt is the problem. if you want to remove the alterator you need to remove the fan shroud. It is a crap job if you do not have a hoist. Again check the serpentine belt

The belt was already changed with a new OEM one. It did quiet it down but the noise is still there. One of the mechanic used a mechanic said it was the ADP.

Very much possible, I did it myself on the street.

Take your time, it'll be tight but you'll be fine. Things will break, it's old plastic- don't be scared. I left some tips & tricks in a comment under TomyBuckets to help others.

Did it earlier this year. take your time. you must remove the fans but you don't have to remove the radiator. you must remove the passenger wheel and the cover to get to some of the bolts from underneath. Make sure you get a piece of cardboard and place it along the radiator fins so your alternator doesn't bang into it and bend the fins as you're removing and replacing the unit. I HIGHLY recommend tying a string to the both the old and new alternator as you're removing and replacing to assist you in stabliizing it. it's an extremely awkward angle and you want to avoid breaking things around the alternator as much as possible, especially the radiator.
the screws that connected the radiator fans to my car were severely corroded and I basically had to drill them out with an easy out.

do yourself a favor and buy some extra screws from your toyota/lexus dealership as alot of them will be rusted and corroded to hell. the bolts that actually hold the alternator in were fine to reuse for me though.
There are some great youtube videos that show you how to do it, including the one above my post. overall it was a pain in the *** but I would not pay a mechanic to do this job for me, probably took me about 2 to 3 hours, including dealing with corroded screws. i had a helper assist me in removing the fans and putting them back in because they easily get caught on stuff like wires.