Does it do it at idle or rolling to a stop. I cant see why it would do it at idle. Mine used to make a very severe bang when it was rolling to a stop, It only banged once but it did it every time, My 2nd gear clutch was fried. Yours might be that it isnt engaging all the way, You have to adjust the cable on the top off the tranny. If you put it into park withh the car still rolling, you would get several clicks or something like that, DONT TRY IT. But if the cable isnt engaged all the way I could slip when acelerating and not full engage the lower gear when decelerating so it would keep trying until it got the gear it there.