Need some advice, gearing/fuel mileage.
Hey I know we have a big thread on fuel mileage going. I’m considering a 2020 Ram 3500 Crew Cab with the HO Cummins/Aisin and it has the 4.10 gears and it’s a dually. On a test drive it appeared to...
Forum Discussion
otrfun wrote:
Our '16 Ram Cummins' overall gearing in 5th gear with a 3.42 rear end is more or less equivalent to a 4.10 in 6th gear. After numerous cross-country trips with various 10k-12k 5th wheels and TT's we've noticed no difference in fuel economy driving at 65 mph in 5th or 6th gear. We always tow in 5th to reduce downshifting (and wear and tear to the tranny) and to keep the Cummins more responsive (at 65 in 5th it's at 1,700 - 1,800 rpm, operating at peak torque). Another added plus, the exhaust brake is also much more responsive.
IMO, the only situation where the 3.42 or 3.73 gears *may* have an mpg advantage is driving at 80 mph EMPTY in 6th. I could see a possible 1 mpg increase in fuel economy vs. a 4.10 in 6th at 80 mph.
Me, I can't see the logic in purchasing a $70k-$80k truck that's main purpose in life is towing/hauling heavy, then reduce its tow capacity via higher driveline stress with a 3.42 rear end . . . over a possible or, at most, a negligible increase in fuel economy. IMO, it's a no-brainer to go 4.10---unless your main goal is a slight increase in fuel economy driving at 80 mph EMPTY.
YMMV.
Good post!
I think a lot of the need or want for better fuel economy depends on how it will be used and how often the truck will be loaded/unloaded.
For the first 2-3 years of ownership, I used my truck as a daily 40 miles one way commuter, towing various trailers ranging from 4k-13k, and countless trips to the farm(50 miles away) and deer lease(153 miles away). I was putting around 30k miles on my truck a year during that time and fuel was about $3.00 a gallon. Slight mpg improvements had more of an impact due to how I was using the truck back then so a 3.42 was a no brainer even if another option was available. Now I have a diesel commuter car that gets 45 mpg so the fuel economy in my truck is not as important as it was back then even though I still like to get the best mpg possible for how I am using it. If I would have had my car back when I bought my truck, I would probably gone with the shortest gear available. However, the 3.42 was the only option.
