My Mitsubishi Galant 2000 ES 2.4L 4G64 is shifting crazy. Every gear won't shift up until 4,000 RPMs. Sounds like I'm just redlining it the whole time I'm driving. Acts like it wants to get stuck in gear sometimes. Transmission fluid is a little dirty and barely low. Also all of a sudden likes to jerk when shifting instead of smoothly transitioning . Any body have any idea what this could be ??