I am parting out my 4th get 3sgte that started knocking. Since I caught the knocking early, the only part that was damaged was the #4 piston. I replaced that piston to keep it as a set of 4. The crank will need to be polished, possibly machined but did not have any deep scratches. I am selling them on Ebay. The list and the links are below. 3sgte Alternator http://www.ebay.com/itm/302208794690?ssPag...984.m1555.l2649