2000 Tahoe OBS with 5.7 Vortec and 4L60E at 120k miles

I was driving on a rocky 2 mile stretch of road back and forth at a jobsite for about 8 days. I was using the first gear majority of the time driving there as I had to go up and down steep rocky paths. At the end of one of my short drives I came to a stop but was unable to shift the transmission into park and turn off the vehicle. The shifter lever was stuck in first and I could push it up into second but it wouldn't go further. I had a buddy jump in and hold the brakes so I could go under and try to shift it with my hands but again I was unable to push it further up from gear 2. I ended up using a hammer and was able to get it "free" and hammered it all the way into neutral. After that, the shift lever inside the cabin was once again able to move and shift into different gears and put the vehicle in park. I drove back home 300 miles and the transmission sounds, shifts, and drives the same way as it did before. However, I am afraid I broke something because the shift lever requires much more force to move up and down. It also doesn't click into gear as it used to. I just have to pull it down enough to go from P to D, it doesnt really "click" as it passes through R and N. 

I got under the vehicle and its obvious that a rock hit where the shifter cable attaches to the lever near the side of the transmission. However the cable is intact obviously as I can shift from inside the cabin. The only other part I see is the neutral safety switch and a metal piece which comes out of the transmission and attaches to the shift cable. Is the issue with one of the external parts or do I have internal transmission damage? Any chance I can do a test to find out? All the transmission shops near me are booked for the next month and I want to do something about it in the meantime.

Thanks