2010 Honda Civic Torque converter shudder

I bought my used Honda civic with 59,000 km. I did regular oil changes and all, and also the day I purchased it I was told my car would let me know anytime I needed a service, the only service it ever needed was oil changes. A few months after I noticed imy car shaking in the front end when driving between 25-30km. Thinking it was my tires I waited till winter when I put brand new winter tires on it continued shaking occasionally at that speed. I took my car to my honda dealer and they test drove it, they told me that it was probably my tourque converter shudder. They also told me I should go to my local honda as the job would take a day or two. My dealer also told me this was covered by my warranty. When I went to my local honda dealer though, they told me I neglected to change my transmission fluid. They changed it for me but my car still shook on my way home after the service, although much less then usual. Is this a quick fix or permanent solution? Is my local dealer just trying to get me out of their hair or make this problem my 'fault' so they won't have to fix my car using my warranty?