Detroit Series 60 sounds like a freight train ! PLUS, I'm only getting 7 MPG bobtailing !!

Thanks for the tip. I plan on getting balanced injectors first and if funds permit, installing a Full-Tilt exhaust manifold, BW 171702 turbo and mild tune.

 

Yes, I did. It was the right side motor mount.

The other sympton was that whenever I turned left, the noise would increase just like a bad front wheel bearing. Plus the steering wheel vibrated like an orbital sander.

Turns out that the old motor mount was rubbing steel on steel and that made the engine chug like a freight train. My truck's cab noise went from 80-83 dB to 72-75 dB after changing both rear motor mounts. I installed the newer DD15 mounts and have been meaning to post that but I'm just too busy hauling loads right now.

My old mount looked fine from the outside but this is what it looked like after it was removed and fell apart.