starter engaging when I put it in park???

[gonnuts]

My truck does this occasionally when I shifting R or mostly Park. For the longest time I couldn't figure out what it was it sounded like something was hitting the flex plate or something, but I know that wasn't possible. Yesterday adjusting the shifter linkage/ rev. lights and just had the key on and was playing with shifter the starter kicked in,WTF. So I tried to make it do it again and finally succeeded but doesn't seem to be any consistency, it just briefly kicks in like your bumping the starter to turn the engine a bit. I think it would have to be something to do with N safety switch but I'm no wiring expert. Anyone with more electrical knowledge than me ever heard of this or have any ideas?
Thanks, Jim