I have a 2008 GMC Sierra with a 4.8 in it now. I am towing a 7X14 enclosed cargo trailer with a 1000 inside. This thing is a dog going up hills or if the wind is blowing at me. I really need a new truck. Went to a few dealers already. I have talked to a few people and they said to get a 2500 diesel. The difference between a gas and diesel motor is about $8,000. Do I really need a diesel or would any motor over a 6.0 work for me? I'm not sure about Chevy, Ford or Dodge yet, just started looking.