Can you get the Allison trans with a gasser these days? I know you could in the past.

The only gas engine that had an Allison behind it, was the 8.1, and it was the 5 speed Allison. The six speed that's in the new 6.0 trucks is GM's 6L90.

Just bought a 2012 lt 4x4 6.0 gasser and 6 speed trans crew cab. So far I like it only 2500miles on the clock. Eats gas...... when towing, not bad on the highway with no load. 2k at 73mph. I am still trying to find the sweet spot. Trans is really smooth in auto but in manual its a bit jumpy/clanky.