My 2016 lml duramax vibrates whenever im in drive and stopped it did it for a week then stopped for a month and now started back up again the vibration is coming from under the front of the cab
Truck is deleted and the up pipe is modified flex joint is cut and welded and the exhaust is not hitting anything it only does it in drive at a stop i can be in reverse park ir neutral and it doesnt vibrate at allExhaust hitting a crossmember can sound and/or feel like someone is hitting the frame with a hammer or it can sound like a rattle. An exhaust leak can cause a vibration as the exhaust pulses bounce of the firewall. If your truck is deleted(EGR cooler removed) it is possible that the passenger side up pipe flex joint is ruptured.
By power brake do u mean engine break and it doesnt happen when im moving only when im stopped and it doesnt do it on acceleration or when coldSounds like the engine is moving and allowing something to touch the body or the frame. Possible bad driver side engine mount. If you power brake it in drive and the engine rotates towards the passenger side then the driver side mount is broken. Very common issue.