Ok, so about a week ago, I noticed when I shift from fourth into 5th, the stick like shakes really bad.. Almost like it's gonna stall? Not the normal slight bobble of a stick shift. It happens EVERY day now, like clock work! Doesn't happen with any other gears-just 4th to 5th! What is this? And do I need to take him in? He's a 2009 JK 6 spd with 32,000 miles. Only had him 4 mths, and it used to be smooth shifting all the time!! I will take him in if I have to, he's a Jeep certified purchase. Is something bad wrong?? Help!! Thx!!