1997 Chevy Truck Transmision trouble

I cant really think of anything on the front of the engine that will change the way the trans shifts. First remove htedrive belt after it has been warmed up and is making the noise, if the noise stays it isnt belt driven adn may be a trans pump whining and transmitting the noise through the engine. All trans fluid is relatively thin, the color and smell is what you are looking for. It should be red adn smell kind of like plastic. If it is dark and smells almost like aburnt clutch, you may have a problem. Try a trans service first, at that mileage you should be on your second one by now. Is or has the check engine light come on? If so have the PCM scanned for trouble codes