2005 ram 2500 4x4 quad vs. 2006 ram 1500 quad 4x4

No doubt the 1500 will pull it fine. I had almost the same truck, but mine was a 2003. It had plenty of power. The real problem will be payload. Mine was a 4x2, and I was right at my payload limits. Your trailer is 800# lighter than mine, but that translates to only 120# (15%) less weight on the tongue. Your 4x4, however, will have 300-400# less payload due to the weight of the transfer case.