2001 Grand Prix GTP 3.8L L67 1XAB Transmission

Before I buy a trans I would like to know if my trans can be repaired instead of replacing it completely.

Problem 1:When hitting passing gear it doesnt go into gear right away it stay in the higher gear for a brief time then it will hit it. Then it will most times have a slight bang/knock sound when it hit passing gear. It doesnt do this in any other gear just so you know.

Problem 2:On take off and under acceleration there is shudder/vibration coming from under the car. Can this be torque converter shudder, tires, cv shaft or strictly unrelated to the trans which seems unlikely.

Can these be fixed on my trans or do I have to get a complete tear down/rebuild?