I am postin for a buddy. He has a 2K 3500 4x4. 5 spd. His turbo has an oil leak. Is this a bad problem? His TD seems to be underpowered compared to others. It has 130,000 miles on it. He changes the oil regularly and fuel filter. It has a K&N FIPK on it. And it looks as though oil leaks from around the bottom somewhere too. Any help would be greatly appreciated.