okay so i bought a 99 durango with 60k on the clock and two slung rods.... i found another used motor with 108k and purchased it from a salvage yard... when i started to install new gaskets i found just as much sludge buildup as the old motor....1/4 inch thick in some places..... now i know sludge buildup has been common in these motors but what should i do? how should i go about cleaning up the sludge? or should i just try to get another one from the salvage yard? short on cash and just want to get my durango on the road