I have a strange problem with my transmission. During highway cruise when the throttle is released and the vehicle is decelerating at 60-75 mph the torque converter clutch engages and disengages very quickly until the vehicle is below 60mph. This would occur 3-4 times in succession until the vehicle is below that speed. This occurs with the stock transmission tune, I have a 4l80 and 2900stall converter. Attached is a plot of the timing when this occurs - also strange. Please help!