So I have been tinkering with several things on my 99 lately. In the mean time I have been driving my 79 4x4. Leave the house this morning headed to work. Hit a big bump in the road and the shifter jumps into neutral. Dang it, put it back into drive but it jumped up again. Thinking to myself what the _____! Drive the rest of the way to work holding my shifter down into drive. Park the truck and go into work thinking about what could cause it. Went out at lunch and looked under the truck and FOUND THE PROBLEM. Top shock bolt had fell out and was gone. Leaving the shock fully extended up against the shifter linkage. This was why it was hard to pull down into drive but not that hard to hold it there.

Just thought I would share my amazement at how a shifter can jump out of drive on its own.