The customer brought his 2005 Ford Taurus to our shop with a complaint of an intermittent jerk at highway speeds. The customer had gone through the trouble of documenting the times that this jerk appeared, the temperature at which it occurred and under what driving conditions he was feeling the intermittent condition. He also told me that another shop had recently rebuilt the transmission. I took the time to listen to him and to ask several follow-up questions that would help me correctly identify the problem. It occurred only once every couple of days.