Ok I have two questions. I was reading a write up on Stu website about control arm bushings. I was curious as to what the benefits of changing these out is ,besides just for the reason they are old and worn out. Also I am having a very loud "thud" coming from under my TJ. This happens mainly when I am in first gear going a very slow speed. Pretty much when the jeep is in first and pulling itself down the street under its own power without me giving it any gas. When I do give it gas no matter how easy I am when I get on the foot feed it jumps and I hear and feel the very loud "thud". It also happens if I don't shift up perfectly into the other gears. Could this be a trans mount or something else.