just went through the big change. We had a 2006 2500 with a 6.0 gasser. Just not big enough to pull the the 36ft. We had to bite the bullet, and went to a 2007 2500 Duramax with the Allison. So far we love it! The redeison for the Chevy 2007 is great, from everything I have read, the Allison is...