2006 tj wrangler.
Ok so I am going to try to explain this the best I can, but I recently noticed that my jeep is running like its in 4wd. The engine runs louder and sounds like I'm in 4H but I'm not I have to shift gears earlier and gas mileage has decreased. Everything is running ok but I don't know what it could be. The engine before ran quieter and didn't sound like a diesel. Anyone have any suggestions on what it could be.

