I recently purchased a 2000 Buick Century with the 3.1 L V6. The car is in great shape and had only 60,500 miles on it when I bought it. It now has 62,000 miles. I have seen a couple of articles stating that there was a problem with a pressure valve/solenoid in the transmission that goes out and causes the transmission to shift hard. Today, the transmission starting shifting harder than normal, not clunking, but harder than it had been. I do not have any service engine/vehicle lights on, but I am wondering if this pressure solenoid is going bad. Has anyone with one of these vehicles had this problem and if so is it an expensive repair? I am mechanically inclined, but I do not have the facilities to do transmission work so I am going to have to take it somewhere. Any information would be greatly appreciated. Thanks.