For the past several months I have been having a shudder issue. It would only occur between 1500-2000 RPMs and usually while there was an extra load present (ie going up a hill, etc). It progressively got worse and was able to get the tech to go for a ride and feel it (first time out a few weeks ago he drove it and could not feel it, but it was less noticable then). They are replacing both front axels. I will be interested to see if this fully solves it, it is an odd problem, no codes, feels like a mis fire but slightly different and does not affect power Etc. Just passing this along for anyone else, the car is the 09 in my sig, and to see what you guys think. I will update the post, the axels are ordered.