Unlocking in certain situations will get you on down, i think it this vid, if i would have pulled it down into 3rd, or unlocked earlier i would have gained atleast 10 feet, but i tried to lug it. This is with gears, so you could imagine where a truck with stock gears would have fallen off.
http://www.youtube.com/user/timthecarman2004#p/u/13/lBCWlItPXjE
What RPM would your truck fall off, or "choke" like in the video... With the ODL truck this year, it would get down to 2850-3000 rpm and still not fall under that GT45 with a 1.28 housing, but that is about where it would break the tires back loose and jump to 3200-3500...
We were hitting anywhere from 3900-4300 depending on what gears we had in it... Seemed like the higher the gear and the harder we worked it, the better it pulled, but we needed more cam and more fuel in the higher r's...