I have a 2001 Hyundai accent. The car ran great but it would not pass smog. So I pulled the engine and trans. Out. I bought a used engine and attached the old trans to it. I dropped it in the car yesterday. The car started fine but if won't shift into gear. When I put it in D, R, 2, or 1 the engine makes a humming sound but nothing changes. I jacked the car off the ground and tried to shift it manually under the hood and nothing. I also removed the dust guard on the transmission and the torque converter is rotating. Can anyone help me with what it might be. I am trying to trouble shoot before I have to dismantle the trans axle.