Hoping to be towing about 3000 to 3500 pounds up and down a ramp and on flat roads for no more than 40 miles. All this would only be once in a while. 1. Would a 2 wheel drive with a 4.0 be enough or would it be better to get a 4 wheel drive ? 2. Would an empty bed cause problems with traction with the back tires ? 3. Is a 4.0 necessary or would a 2.3 be enough ?