i have a 03 solara i hear a buzzing which i think is coming from transmission when i start it usually for a 20 seconds. sometimes i give it gas and the engines revs with low forward momentum. i have had the a silinoid and a sensor changed on tranny but problems dont show when i take it to mechanic. do i need a new a tranny

Not for sure. Look for signs of slipping or a burned transmission fluid smell.

Could be the the transmission pump going out. You can connect a gauge to it and see what the line pressures are. Check the fluid color. Should be pink/ red, more red then anything. Check for slipping. Listen to see if motor revs but car hardly moves.

so i drove the car another time to work and got the check engine light to come on. noticed definate slipping watching my tach and smelled what i thought was burnt atf. codes showed PO717 and PO741.these point to issues regarding turbine shaft speed sensor and torque converter clutch solenoid. both were changed a week ago. Definately leaning toward rebuilt transmission.