Exchange 2007 mail.queue keeps growing then shuts down transport

view story

http://serverfault.com – I have an exchange 2007 SP2 server where the Hub Transport log files, specifically the mail queue database keeps growing to 4GB, then the Exchange Transport service shuts down. Once I delete the logs folder including the mail queue file, I can restart the transport server. The problem is, it keeps growing to 4GB within 1 hour and the whole cycle repeats. I'm looking for some advise on how to troubleshoot this. I've been trying many suggestions found on google however they all point to fixing the issue once, nothing about stopping it from reoccurring. Thank you (HowTos)