Calling weight police - help
Hello, I am in the process of getting a new setup, truck and 5th wheel. Truck is a 2022 F350 King Ranch 4x4 SRW short bed Diesel. Fifth wheel is 2021 Solitude 378mbs. I am also planning to add Summ...
Forum Discussion
speediq99 wrote:
It looks like this may be a good thread to ask about gear ratio given how many here run duallies.
I have 3.55 or 4.10 option for the F350 Dually. Towing 16k.
I like running around at 65-70mph.
Read somewhere that 4.10 mpg really suffers after 65mph. No trying to save on fuel as much as trying to preserve range. I also enjoy a quite ride.
A 10 speed will allow me downshift with a 3.55 to get the rpms higher for the right torque.
Should I go with 3.55?
Would a 3.55 climb a 6% hill just as fast as a 4.10?
I ordered the truck with 4.10s but I may end up using it 30-40% of the time to travel empty. Thinking about changing to 3.55or.
Per the Ford towing guide, the 3.55 is rated for at least 31,300lb 5th wheel, so you aren't even close to the limits. The 4.10 only increases that to 34,700.
With the 10 speed, it will just pick a different gear if you are climbing a grade to result in the same overall gear ratio between the engine and wheels...the engine will never know the difference and you likely won't either as the engine will be turning the same RPM.
4.XX rear ends made a lot of sense back in the days of 3 speed transmissions, there was so much space between gears that when towing, you often wound up either lugging the engine in top gear or running high RPM in a too low gear. With 10 speed transmissions, it can always find a gear that puts the engine in it's ideal RPM range for the load.
