With some of the really big trucks, its almost easier to shift without the clutch than with, lol
So long as you are just able to slip the shifter in (aka, no forcing it) you arn't likely to hurt that rock crusher tranny too badly
I used to do it to my tranny once in a while just for kicks, just put the tranny close to the gear you want, and let it very lightly bounce off the gear you want while changing engine rpms, and suddenly it slips right in like you hit the clutch, quite cool
