Touareg :: 2005 V8 Transmission Not Shifting

It wasn't until very recently that my 2005 Touareg (V8) just dumped a plethora of problems on me all at once. System Fault Workshop, Brake Assist Failure, etc... However, one of the more serious and annoying issues is the automatic transmission.

One day, the action of pushing the shifter over into the Tipronic slot was stiff and unyielding. A little pushing here and there and it popped in there. No big deal. A few days later, once in Tiptronic mode, it refused to downshift, it would only upshift. A few days later, it refused to shift at all once pushed over into Tiptronic mode. Upon removing it back into Drive mode, it also refused to shift there.

Now, to my surprise, my Touareg will not shift gears up or down unless it is in Sport mode, which is not too great for the long-distance commuting I have been doing lately, I would like my 5th gear back. I have been unsuccessful in searching any situations similar to this and I am worried about what kind of parts could have been damaged under the shifter... but I am skeptical about what electronics could be broken that tell not only Tiptronic but also Drive mode not to shift whatsoever, and that it may be more deep-seeded than some flimsy plastic under the console.