When accellerating fairly heavily and windows closed I can hear a rattle type of sound in the cab located roughly around the hump in the floor where the allison sits.
I remember a post on being able to hear the allison more than a 4l80e or other tranny because of its mass. Just wondering if any one else gets this as well. this is the 2005 in my sig.

Dieselmax182, I have never heard that noise while accellerating. However, the crossmember underneath has been known to loosen up (mine did) over time. Mine was more of a popping sound on turns though. Might want to check it out. Jerry