I had an '07 Impala LTZ. At 100,000 miles I had the transmission flushed at the local dealer. That was the first service it had received. I noticed the transmission slipping occasionally at 135,000 miles, and was surprised because of the service about 7 months earlier. I drove it for another year and a half or so, and then traded it off after owning it 49 months. It had 210,000 miles and the transmission was no better or no worse. The dealer estimated the transmission replacement at $3500 and the car booked for $5800 due to the high mileage. I figured it was time to trade because the rest of the car was original with the exception of the water pump, tires and a battery. I figured it was going to start "nickel and diming" me to death. I traded it for an '11 Impala LT. To be honest I liked the '07 better because it had the 3.9 engine with the Active Fuel Management, which GM discontinued in '08. The 3.5 engine in the '11 LT does not get as good gas mileage as my '07 did.