2002 Kia Sedona 2002 Kia Sedona engine codes transmision pr

These symptoms are as reported by my wife. I have not had the van do this to me personally yet. My van will intermittantly have a problem when I start the engine then put it in reverse it starts to shutter violently and the RPMs drop to almost zero. If you put it back into park and shut it off, then start it again it often doesn't do it again. The check engine light is on and I had the codes read and they are as follows:

P0755- Underdrive solenoid valve system
P0760- Second solenoid valve system
P0770- Reduction brake solenoid valve system
P0350- Ignition coil primary/secondary circuit

Just looking at the names on the codes, my first thought is transmission change. How hosed do you think I am? Are any of these items located inside or outside the transmission or are they not even related? Any insight you can offer would be appreciated.