Surging Trans.
#1
#3
It can't be the torque converter. If the trans is in park none of the clutches would be engaged, but the torque converter will still be turning the input shaft. If the converter clutch were locked it would turn the input shaft a bit faster, but it spins either way.
What is happening is that a clutch inside the trans is dragging a bit. It is not that unusual, and it doesn't hurt anything. You could have the trans rebuilt with bigger clearances in the clutch packs, or you could switch to synthetic MERCON fluid. Synthetic doesn't get as thick at cold temperatures so it won't drag on the clutches as much.
What is happening is that a clutch inside the trans is dragging a bit. It is not that unusual, and it doesn't hurt anything. You could have the trans rebuilt with bigger clearances in the clutch packs, or you could switch to synthetic MERCON fluid. Synthetic doesn't get as thick at cold temperatures so it won't drag on the clutches as much.
#4