My front and rear chains are super tight on the top, one of them ripped the nylon off the chain tensioner. The bottom of the chains are slack. How do I equalize the tension? Also the sprocket on the center axle under the jack shaft is out of place, it's too close to the body and caused the chain to jam against the side rails. I think there is a clamp on the axle that can be moved if I loosen a set screw? I seem to remember this from when I was replacing bearings and a snapped axle.