1994 GMC Jimmy Missing Bolt for transmission?

I was told that a bolt or something is missing on my transmission causing it to make a noise, however I wasn't sure if the person who told me this knew what they were talking about. Is this true? Also, when I make right turns (mainly) I hear a clunking noise, and it seems that I can feel something moving underneath the floor on the drivers side. This sometimes happens when I go through potholes as well. I had my front shocks replaced about 2 months ago, and while it did make an improvement, because the "clunking" was very bad, it still makes a noise. And help would be appreciated!