So i was went to start up my truck the other day and it sounds like a freight train. metal on metal smacking almost. i have a 2002 f350 with a 7.3 and i just bought it a month ago, the motor was just swapped to a 170k mile motor and i still have the other one in the garage with 289k on it.... the flex plate was recently replaced and now this #### happens. i took it to to garage and they said there is some metal flake in the oil which they are indicating is a bearing issue and they want me to replace the motor, then i pointed out that when driving above 20 miles an hour it completely stops and it also stops when the truck is in reverse or it at least gets really quiet. please help me!!! i have them dropping the tranny tomorrow to check the flex plate before they charge me $8500. should i just put the old motor back in it? any advice would be helpful seeing how this is my first diesel and i dont have tons of money to throw into this thing.