BUICK TERRAZA DRIVETRAIN

My Van Has Recently Started This Hesitation When Accelerating From A Stop Or Almost Stop, Say At A Stop Sign Or Slowing Down For A Turning...

Where Is It Located?

I Was Told That I Need To Repair The Wheel Bearing Front And Rear And The Rear Knuckle. What Is The Knuckle? Why Is Connected. Any Ideas...

Gear Shifter Moves But Will Not Lock Into Place Or Change Gears. Was Fine Twenty Minutes Ago.