Recently while driving at freeway speeds the vehicle will jerk a bit and the speedometer drops to zero and the wrench symbol comes on. The cruise control doesn't work and passenger airbag becomes disabled as a result. I can keep driving but have no idea how fast I'm going. If I stop the vehicle and turn it off and restart - it goes away and everything returns to normal - until it happens again usually at at later date. My code scanner stores a PO720 code. On older Expeditions - all indications point to the output speed sensor on the transmission. But I cannot find an output speed sensor listed in any parts listing for this year expedition. There are ABS wheel speed sensors and those seem to be working properly (I have a scanner that checks ABS). Looking for 1) where does the vehicle get it's speed for the speedometer? 1) Any ideas on what could be causing this?