I have a 2005 with the 6 speed manual transmission. It has about 13600 miles on it. Yesterday I took a 300 mile trip in it and noticed a vibration at about 70 mph. It feels like it could be coming from the drive shaft. It feels like a shudder and it is not constant. Is this common and where should I begin checking for issues. Could it be U joints or is this a transmission issue. With only 13k on it, this SSR has spent most of its life in a garage. Any suggestions are appreciated. I’ve only had it a couple of months and I’m still getting to know it. Thanks!