Welp, after fiddling around a little bit I found the transmission interlock thingy. I disconnected it, but no luck. Then I figured something could be wrong with the shifter T-handle, and sure enough even though I could press the button, it was not pushing down the plunger. I removed the T-handle and actuated the plunger by hand and I was able to shift. I reconnected the transmission interlock connector and was still able to shift, so it was the T-handle after all!
I look at it this way... Purely being able to ask the question on this forum was enough to help me figure out the issue!
I look at it this way... Purely being able to ask the question on this forum was enough to help me figure out the issue!