Th350 column shift issue

[Mike_The_Grad]

Hey everyone, this just happened 2 days ago. While I was parked at a friends house on a slight incline and in some dusty sandy loose dirt, I started my truck (72 c10) and tried to shift from park to reverse. I was able to pull shifter towards me but I had to really struggle to get the shifter to drop into reverse. I was trying so hard to shift that I was afraid I was going to snap off the shifter. (I've had this happen three times in the last 15 years.) Well it shifted into reverse finally. But now the shifter wont stay in reverse or neutral on it's own. The weight of the shifter alone let's the selector fall from reverse straight into drive. I've already had 2 scares where the shifter fell from reverse into drive and I started to hit the accelerator pedal. Both times I reacted quick enough to avoid hitting what was directly in front of me. So you can see how this is a pretty important issue I need to address. I completely removed the steering column last year and gave it an overhaul. Cleaned degreaser it, painted the outer jacket, lined everything up nice, deburred everything and made sure it was smooth and operating freely. And up until 2 days ago I had zero issues with it. I havent done anything to diagnose what it is yet. I'm not sure where to start. I'm gonna pop the drive pin out of the selector shaft and give it a look. Everything appears normal so far. I did notice that the gear selector detent plate on the engine side is worn down pretty good. To a point that there is not really a step anymore where it goes from park to reverse. Its rounded off. Also it seems like theres a lot less spring tension keeping the shifter in place. It kind of just floats back and forth if you try to pull it towards yourself to select a different gear. Any info or advice on what can be done to either tighten up the spring tension on the selector or help the gear selections be more positive and not fall out of gear?