good morning!, just to add my two cents, at that mileage is a must to replace the water pump, I did it on my 4.8 at 90K because I had this cracking sound coming from the water pump, at the same time I drop the new belts and pulleys just for peace of mind.

Water pump is a little bit difficult to remove since the bottom screw is behind the balancer that the manual recommend to remove it to get access to it but with a little 8 or 9 open wrench you are able to do it...

just patience and you could o it... just get a beer and cheers!!