2500hd rear end gear ratios
 

Is it correct that GM put only 4.10 rear ends in the 2500hd's with the 6.0 engine from say 2001 to 2006? What average fuel economies are people getting? I am looking to buy a used one and had it in my head that I was going to buy one with a 3.73 rear end.

You can expect around 13-15 on the highway. I don't bother watching it in town. I have a hunch that your oil makes a difference - changed from 10w to 5w and went from 13 to almost 16 in the same driving conditions. I know I have 4.10 and I think that's all you'll get off the 6.0