can i put an allison transmission on a 2004 1/2 ton 2wd 5.3 liter chevy avalanche?

[natertot123]

i have a 4 speed stock tranny in now and its starting to go out... i want to put in a 6 speed but i also want it to last longer than the first... if an allison would work... how much would it cost?... if not... any suggestions on what i could put in it? ( i tow quads, a VW bug... jetskis... and sometimes boats)