01ls430

before replacing the engine try this i just did this on my nephew~s car an 04 mazda 6 and it worked order new crank bearings remove the oil pan which will give you acces to the crank and bearings remove the crank bearings only one at a time look at them if you see grooves dug into them there is the problem you will see the same marks on the crank itself you can use plumbers sand paper to wrap around the crank it will take a little time but get it smooth and replace the bearings you will need to torque the bearings when installing you can get the specs online or if you really need an engine the place i use is lkq 1800-423-4006 ext 2895 ask for nish tell him tony sent you

i have ran into this problem before i have a repair sounds like you have metal shavings stuck in the valve body try removing the trans pan and use air pressure to clean it out from a compressor hope it helps you