i found the clamp that holds the muffler loose,tightened it and went for ride,didnt smell any fumes anymore.

 

Thanks for this info. I smell fumes myself from time to time. I'll check mine out.

 

mine is horrible in the cab... But I think the full front windshield is causing the fumes to circulate up into the cab. I stopped into autozone yesterday and got a longer exhaut tip that turns down on angle... It looks a little goofy, but it actually seemed to help quite a bit.