Two problems related to engine belts and pulleys have been reported for the 2010 Ford Fusion. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2010 Ford Fusion based on all problems reported for the 2010 Fusion.
2010 Ford Fusion idler pulley bolt sheered off along with piece of engine block and pulley resulting in a near accident as drive belt, and power steering failed and vehicle would not go past 20 miles per hour (on highway). My wife (5 months pregnant) was driving at the posted speed of 70 mph when the pulley and bolt sheered off. Her car was nearly struck from behind by several vehicles as well as not being able to steer the car herself. Looking at Ford Fusion blogs, this appears to be a common problem that Ford has not fixed in their earlier models. This design and/or stress fault causes safety concerns as well as costly repairs since piece of the engine block can sheer off with the idler pulley bolt.
I have a Ford Fusion with about 30000 miles. I first noticed a hard shift at 10k miles and thought maybe its just a simple fix. I took it in and they reprogrammed the transmission and the service supervisor said that this transmission adapts to the owners driving habits. Well 3k miles later its worse so I take it back and the tech said all the clutches were replaced and two other things were done! I have taken it back four more times and have not had it fixed. It appears that Ford admitted there was a problem with a transmission code that fixes the problem. However, the problem was not fixed and I am left with a vehicle that also had a window motor replaced, some pulleys that were making a whistling noise, and a battery and taillight that went out changed. I don't know if its a lemon, but I smell disaster in the next couple of years! wish Ford would do the right thing and stand by its product.