Faststreak wrote:
I’m not very knowledgeable about this gear ratios just want the one that will get the best economy with my slide in camper and sometimes pulling a bass boat which isn’t very heavy compared to a fifth wheel. The dealer have lots of 410 on the ground none of the others. Still not sure which is best.
Personally I would go with 3.73 and be done with it.  That is the only ratio GM offers with the Duramax; that says a lot.  It is a good compromise of a good pulling truck and solo driver.  I had 4.10 gears in my last 2 trucks and they were great pullers but not so good solo drivers.  I realize 6 speed transmissions change this somewhat but you get the idea.