i know this isnt fully efilive material but i will use my efi live if i think its true. i found this on the allison web site. ive been around diesels for a while and ive never seen one revved to 5000 rpm normaly. ive never been over 3648rpm right because of the tranny limiter can we bump this up useing G0801and get some more revs out?

Safe to operate in dashed red zone.
NOTE: When driving on a downhill grade with a heavy load, the vehicle’s weight and inertia can be great enough to increase vehicle speed and engine rpm without applying the throttle. The vehicle is designed to operate in the dashed red zone. This is normal and will not cause engine damage. However, the vehicle should not be operated in the solid red zone of the tachometer. The traditional brake system should be utilized to prevent engine operation in the solid red zone. heres the link if anyone actually cares to give me an expliantion.

http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA3931EN.pdf

its saying that using the engine as a brake it is safe to almost 5000. but only 3400 with a load on it.
i have seen mine at 4500 (tcm shift, not using the lever) before towing a large load down a steep grade.
i wouldn't raise the limiter unless you have internal work done to the engine or need more mph at the end of the quarter mile. its there to keep your duramax in one peace.

thats what i was thinking thanks