Did a yearly ATF D&F. Car has 135k km. Original fluid inside was a mix of Z1, DW1 and Maxlife from previous drains. Ran out of Maxlife and didn't want to put DW1 in as I heard it's quite low viscosity. So I got some Castrol IMV. Drained about 2.2L out and added back in 6oz Lubegard Red and the rest with Castrol. Not sure if my mind is playing tricks or not, all the shifts seem ok, but when I reach highway speed(100+km/h). I can see the torque converter lockup(rev decrease by around 300RPM). At 110km/h, engine is running around 3000RPM, and when I apply a bit more pressure on the gas pedal, the transmission seem to disengage torque converter lockup, goes up by around 300RPM, settles back down to 3000RPM and then the car would accelerate as normal. Is this of concern? Shouldn't the RPM stay at 3300 when the torque converter lockup disengages? Since I am paying more attention to the tachometer, I noticed this and the feeling of the TC disengagement seems more frequent after the drain/fill. Following is what I found on the Accord normal operation: Proper operation: The car starts at first gear at half throttle. When the speed reaches about 17 - 21-mph the car shifts to second gear. When the speed reaches about 35 - 39-mph shifts to third gear. When the speed reaches about 54 - 60-mph the car shifts to fourth gear. When the speed reaches 60 - 65-mph or more the lock up torque converter engages. This is felt as a slight nudge. Shift sequence ends.