I looked in the 737NG FCOM and I could not find anything that says a chance in rudder trim knocks off the Autopilot, assuming we are in CMD, and not in control wheel steering.
CWS may behave differently because it only works through trim to maintain attitude.
I had thought that maybe the bank angle alarm going off may kick off the autopilot, but in the FCOM, the bank angle alert is part of the GPWS, and the GPWS has no means of turning off the autopilot. The bank angle alert turns on at 35 degrees by the way, and repeats itself as the aircraft passes 40 degrees and 45 degrees.