I'm actually second guessing if I should have gotten the 3.21 instead of the 3.92 axle for the better fuel efficiency. I already have a F-350 setup for towing heavy and this new Ram will be mostly a daily driver. It's nice to know I have the greater tow capacity when I'll need it, but not sure it's going to be worth the extra fuel cost.
I have a 2019 3.92 and had a 2014 3.21, both w/5.7 Hemi.
The mpg is not noticeable to me but the higher RPMs on the hwy are noticeable....since I drive a lot of hwy miles, so I prefer the 3.21 slightly.
RPMs were about 500 less on the 3.21 and it just loped along at 75-85. I loved that.
The 2019 w/3.92 is so quiet/smooth the higher RPMs are not a noise factor.
I don't tow more than a utility trailer so no real need for 3.92. The 3.92 is slightly quicker but both have plenty of merging and passing power with the Hemi.
A great truck with either gearing!
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