Transmission vibration and noise while driving

[Escorttohades]

I have a '99 Ford Escort 2.0 SOHC with 65,000 miles. I notice a constant engine noise (like the transmission is in the wrong gear....too low) every time I press on the gas pedal. It temporarily goes away when I take my foot off of the pedal but is apparent every time I press down on the accelerator. The car also vibrates when shifting, especially when it is trying to shift into a higher gear. It maintains this vibration more at highway speeds. It's very loud on hills and seems to take its time shifting into the next gear. On the highway it sounds like its trying to shift into another gear which isn't there, thus maintaining the vibration. The transmission fluid is healthy looking but may be too full. There does not seem to be any leaks, although the other day, I shined a flashlight up into the engine compartment and noticed it looked wet way up above the oil pan, but nothing that leaks onto cardboard placed on the ground. Strangely enough, the car seems to perform better when the temperature outside reaches warmer temps. Also, when I start the car in the morning, it idles high as it is supposed to and then drops down....when it drops down, the loudness inside the cabin is quite apparent, which I think is related somehow to the engine noise while I am driving. Is this problem a transmission problem or just a really bad vibration problem causing the transmission to vibrate while I drive?