i have a system in my car and i just got a high performance transmission put in it and for some reason when i play a song or any music my subs will hit but nothing will come out of the stock speakers in the car ...why would this be thanks

 

The stock head unit is designed to work with the factory speakers/amp, to install a new head unit you need to run all new wires or get the special converter box from crutchfield. or you could cut the wires from the speaker/amp setup and bypass the amps. the amp's are connected to the back of the speakers in the doors.

by the way, it has nothing to do with the new trans being put in.

 

it isnt a stock head unit there was a diff head unit put in.... it was workin fine until they put the tranny in cause they have to disconnect the battery and that could have done something to the amps

 

Try checking the fuses for the amps.

 

If the amps were left on when the battery was molested, there is agood chance that a voltage surge may have fried them or blown fuses.