Pretty easy job to disassemble for inspection. Where the work comes in is when you get to replacing parts. At minimum, you MUST check/adjust gear end-play. Do NOT overtorque the (6) small bolts that hold on the cover plate. If the scoring on the cover is not severe, you can sand it smooth by gluing a piece of 400 W/D paper on a square of plate glass or aluminum plate, then use WD-40 and a circular motion to remove scratches. Pack the new gears with Vaseline, pull the cam sensor, and use a primer tool to build oil pressure before firing the motor. IIRC, torque on the cover bolts is 120 in-lbs, and the gear end play is 0.002" - 0.005"... Oh, and CLEAN EVERYTHING twice!
