Got my 1555 running today, started right up oil pressure at 20 let warm up then it went to 10 when I reved it up to 1500 rpm it started a vibration sounded like rear of engine, hard to tell though, tried another oil gauge amd same thing low pressure, rear sprocket and chain is worn bad so I pulled engine and removed pan and #4 main bearing it was smooth with normal wear, crank looked good but ther is small chunks of metal in pan, needs clutch springs are very loose, pilot bearing was apart, thats enough to vibrate but I'm going to disassemble the whole engine to see where the metal came from, any suggestions and where is the best place to get parts for this tractor? It has 3800 hous and nothing has been done to it. Thanks again.