Exact same problem as mentioned in the other comment - even the shuddering when idling with the AC on. We asked the shop we use and they couldn't find any similar problems. No other issues shifting up or down. My main concern is that this is some sign of future transmission failure in which case I would probably stop putting general maintenance money into the car.

I have had this issue since I bought the car last march. It had about 110,000 miles on it and shortly after I bought it I noticed that the transmission shudders when going in to overdrive while going up a hill. I live in Kentucky so that is often! I have also noticed that it shudders when the air conditioning compressor kicks in too! Weird!

I added some transmission additive that was supposed to eliminate the shuttering but it didn't help.

Any ideas?