When I come to a light, I'll be sitting there and I'll feel/hear the trans just kind of bump. There isn't any lag ever downshifting into 1st, I can be going down the road and stop at a stop sign for a second and instantly go, never an issue starting in first.

Just every now and then after sitting at a light, after a few seconds, you will feel/hear this bump like it's doing something late. Not sure what it is.

Any ideas?

 

Are you sure it is the transmission? Could it be one of the brakes sticking or maybe a bad u-joint? How about a bad motor mount?