Originally Posted by tinypanzer

I'm still not convinced the problem is not in the trans. You say the problem happens every time you start from a dead stop. Well, let's use our imaginations for a second..... Any slop in the drive train will get taken up when you shift from park or neutral into drive, right? The torque from the trans is supposed to always be present on the drive train when the car is in gear. This is why the car starts to move by itself when you take your foot off the brake. So, that slop goes away the very first time you go into gear, right? Okay, so how then does it re-appear at every stoplight unless the driver is shifting to neutral?

The only way this could be happening is if the trans is not applying torque to the drive train at all times, and that points to trans problems.