Help!!

Sooo, I’m planning on heading down to king knob wv this weekend for Memorial Day and my birthday.. Just got my stereo system installed and spacers will be put in tommorow. However, just pulled it into the garage and upon take off I hear a clunking noise like something flopping loose more towards the rest end. Somewhere behind the seats.. Stopped and took off a few times and it did it every time. Took it for a spin, noise is only on take off. If I could describe it it sounds like rocks in a bucket getting tossed around almost. Kings Knob is 4 hours from home and I don’t really want to go clear down there just to break but then again I really want to go lol. Could this be just a minor problem or maybe some of you guys know what it is.. I have a gut feeling it’s something with the clutch but it’s so hard to tell. Please give me some answers!! Lol