thinking of buying a new cummins diesel what size gear do you all like best i will be towing a trailer the truck will be a auto

hell i have 4.10s in mine and it pulls fine, about 2400rpms at 70-75mph

mine has 3.55s pulls great also. runs bout 2000rpms at 70, 1700 at 60

I have 3.73 gears with my 05 model and it runs roughly 2000rpm at 70. Really about 72mph. I dont do much pulling. Only thing I have pulled was about 5k and the truck didnt even know it was back there. Gas mileage on the overhead went down .2 mpg. I get nearly 17mpg with my gears with mixed city and highway driving. I hope this helps.