99 Tahoe codes P0753 & P0719
 

99 Tahoe, 4x4 2dr, 5.7L, Auto trans, 127k.
Newby here, so be kind.
Shifting was funny, so when check engine light came on, I got friend to pull codes.
Now I have been researching and looks like a trans service would help and replacement of the coded solenoid, but also hearing about ignition switch.
Havent had any other trouble, and havnt been able to find both codes inconjunction anywhere.

I think I will start with the service, and see what happens, but does anybody have any other things I should look at? Any help is appreciated.
Mike