I've switched to 305/65R17's, do I NEED to switch to at least 4.10 gears or will the stock 3.73's do the trick? I guess what I'm asking is what, if any adverse effects could I expect if I don't change to 4.10's. It's a daily driver that sees gravel and light trailing once in a while.

 

Your 3.73 gears will be just fine for those tires. If you got the 4.10 gears for practically free, then it might feel beneficial to upgrade.

I run 35" tires on my 3.21 gears on an '08 6speed every once in awhile.

 

I have 315/70/17 on my 2012 daily driver with 3.73 gears and auto tranny. With the bigger tires, I've had some loss of torque which is causing more frequent down shifting running up some of the longer/steeper grades around here on the highways at the speed limits. Other than that, she runs great with the stock gears.