buzzing noise when shifting
 

Last night i had my car windows open and my radio off and i noticed when i shifted into reverse or drive there was a buzzing noise for about 1-2 seconds. Is this normal or should i have this checked out. I should also add that for sometime now when the car shifts from 1st to 2nd and 2nd to 3rd it shifts rather hard. sometimes however when it shifts from 1st to 2nd it seems like its lagging a little bit and it takes a little longer to get into 2nd. i also noticed that sometimes when i coast through a stop sign and and then push the gas the car doesn't respond right away and it jerks hard when it does. anywho, your help would be appreciated, thanks.