Ok, that's good - no issues internal to the transmission...So, when shifting gears using your column shifter, you should have the following detents available to you from Park:
1. Reverse
2. Neutral
3. Drive
4. Drive3
5. Manual 2nd
6 Manual Low
From what I recall from replacing my own cable (03 Tahoe Z71 4WD, which should be the same cable as yours), I never adjusted it...I simply installed it and went. I'll have to double check but I think there's a small bracket or retainer on the Tcase to route the cable...Which leads me to my next thought which whether or not there are two different cables: one for 2WD vehicle and another for 4WD vehicles...Perhaps someone can weigh in and confirm/deny...