U can get a product called all weather brush which is a paint on cold bitumus sealent.We use it at my company for all our garage repaires and it works a treat.Its very easy to apply with a large paintbrush.
If u have a ladder,just get up there and check that the gutter clips are all screwed in and secure.The only way a gutter could bang is if it was hanging off the fascia also check the the down pipe clips.