Check the Seagate web site for exact model number of your hard disk and whether or not there are any known issues with some firmware releases that have been fixed by an update.
If you believe your drive is exhibiting the issues described on the web site and you're prepared to risk "bricking" it, backup all the data, download the firmware update, disconnect all other hard disks and apply the update.
I'm assumimg you've run a thorough surface scan of the hard drive and found no bad blocks, pending sectors, etc.