Toyota Repair: 1997 Toyota Camry, toyota camry, transmission problem

Question
I have a 1997 Toyota Camry, 4 cylinder, which has been a wonderfully reliable car for the last almost 11 years. It was two years old when I bought it. Lately I have noticed it has not been shifting into fourth gear as smoothly as it has in the past but it still runs fine. I have kept the car maintained and had the timing belt replaced less than two years ago. If the transmission goes do you recommend replacing it with a used one? How would I go about finding a good used one?

Answer
In this case a used transmission may be the answer, most larger cities have salvage yards that stock used units, they can also be located online. I would wait a while to see if this gets any worse making sure the fluid id clean and up to the full mark, maybe changing the fluid would help, then again, it may not be a major transmission problem, it may be something else like a shift solenoid malfunction which eventually should turn the check engine light on.