Alternator/generator/regulator problems of the 2005 Nissan Quest

The first failure was a complete loss of all electrical power on the vehicle while driving and in traffic. This required a walk home and tow of the vehicle. It would start with a jump but then shortly after would completely die. The dealer diagnosed this as an alternator failure and replaced the alternator. The second failure is a periodic slipping of the transmission out of gear. The first occurance felt like slipping in snow then grabbing. We called the service department and they told us if there was a problem with the transmission an error light would appear on the dash. The second occurance 2 weeks later was a complete loss of accelearation when pulling into traffic. The vehicle was pulled to the side of the road where it felt as if it was in neutral with engine reving but no power to wheels. We verified the shift was in d and the dash indicator said "d". We looked for any trouble lights on the dash but saw none. We turned the vehicle off once and restarted with the same results. We turned the vehicle off a second time and restarted. This time the transmission engaged and the vehicle drove normally. We took the vehicle to the dealer where they test drove it and found no problem. They also found no error codes in the computer. The dealer is now waiting for technical direciton from Nissan and I am waiting for a return call from a Nissan consumer affairs regional specialist.