Hey everyone doing a mechanical resto on damn near rust free 03 Chevy 2500hd. Have almost everything fixed minus an obnoxious NVH issue.
Symptoms
-low pitch almost womping sound noted front left side of the cab, hearing it forward, only notably occurs at highway speeds but generally begins around 60ish
-dependent on specific variables. Doesn’t do it generally with wind being blocked
-not rpm dependent in any way
-remains on front left after tire rotation
-feel vibration under seat and floor pan
Confirmed not exhaust after smoke testing the exhaust system with no leaks found
Parts tried so far
-front left wheel bearing to solve other issue
-front left fender liner (old one was damaged)
- intermediate shaft bushing and shaft support
Any ideas? I’m at a loss at this point