Trans slipping high gear

[Max(SD)]

I rebuilt my transmission last winter, but have not driven the truck that much over the summer. Had it out the past week and everything is running fine. This afternoon, coming home, in second gear transmission would not engage, could hear the spinning but it was not catching the a gear. I took it out of high gear and into low gear, and all the gears engaged, then I pushed it back into high gear and it began working, then it would slip out and just spin. It seem that my high/low gear lever is not fully engaging high gear and slips out through normal driving vibration. How do I adjust this?

I took the floor boards out. As a side note, I realized that I should have put the driver side and passenger side floor in first before the center tunnel cover. I had to take everything off. What a pain.

Well here is the photo

[Max(SD)]

Also while we are here, I have noticed that when I engage the 4 wheel drive and then switch the high to low gear and back, the 4 wheel drive yellow lever does not pop up on its own, I have to guide it upwards.