Ford Dually rear end preference

[Slideplayer]

Hit the scales with my current truck and camper and I’m right on the max of the truck GVWR and payload (11500 and 3450 respectively). Im looking to make the move from a SRW F350 to a DRW F350. Im considering a dually Lariat with a 3.55 rear axle, same as my current SRW. I have no problem pulling our Monty with our current setup 2016 F350 SRW 6.7 w/3.55 rear end, it s just the weight that makes me nervous. We travel interstate a lot in our journeys and i typically run the speed limit and 5 over. 65-70 mostly. One truck that i looked at had the 4.10 rear which I’m sure will get up and going quickly! The newer truck also has more torque and hp than my current truck and has a 10 speed auto tranny vs my 6 speed.
Are any of you Super Duty guys out there running the 4.10 gears with that 10 speed and how does it perform on the highway? Any noticeable sacrifice in fuel mileage with this rear end and in what gear and RPM are you cruising at say at 70 mph?
Lastly, I would hope going from a short bed SRW to a long bed DRW that the ride and stability will be much improved, right? Just a pain to park in tight campgrounds!

[Rotnjonny]

For what it’s worth….. we have a 2022 F350 DRW with the diesel and 10 speed. It has the 3.55 limited slip differential. Our 2022 Monty 3791RD weighs 16,000. Along with the truck and an extra 60 gallons of diesel in an aux tank, we are just under 27k pounds. We have no problems or issues. We are full timers and have put nearly 25k miles on the rig in the last 16 months. No problems or issues with that gear set. Pulls like a train. We cruise at 70 on the interstate. Fuel mileage pulling the 5’er runs 10 to 11 on the highway. The 10 speed is a significant improvement over the old 6 speed. I too had my reservations about the 3.55. I am not disappointed at all

[scottz]

I wouldn't lose any sleep over it; either rear end will be fine. I have the same trailer as you and I have a 4:10 rear axle. It pulls great, but so did my previous Ford with 3:73's. Running 65-70 in 10th gear, I think it turns about 1800. I get 11mpg towing and 13-14 empty; I assume the 3:55 might do a little better.

[Lee-CI]

Originally Posted by scottz

I wouldn't lose any sleep over it; either rear end will be fine. I have the same trailer as you and I have a 4:10 rear axle. It pulls great, but so did my previous Ford with 3:73's. Running 65-70 in 10th gear, I think it turns about 1800. I get 11mpg towing and 13-14 empty; I assume the 3:55 might do a little better.

Interesting discussion on the 4:10 vice 3:73 gearing. I too had had reservations about the 3:73 gears. Our previous 3/4 ton Ram had 3:73s with 20" wheels. The lightly used 3500 Ram DRW we wound up getting has 3:73 gears with 17" wheels, so thankfully wound up being a non-issue. I do grumble at times when getting only 17 - 17.5 MPG not towing, but sounds to me like we should consider ourselves fortunate as the truck weighed in at a touch over 10K before we added the 45 gallon aux fuel tank. Both trucks pulled extremely well, but watching the 20" rear tires sidewalls flex on the 3/4 ton even when cold inflated to 80 PSI got to be more than my nerves could stand.


Edit: As an unexpected addendum to this, we also wound up consistently getting 1 1/2 MPG more when towing since we changed over to disc brakes on the MHC. I thought I was nuts for the first couple of trips calculating the best mileages at right at 12 MPG, but this has consistently been the case since the brakes were installed 11 months ago.

[DutchmenSport]

I've never owned a Ford. But I guarantee you, you'll experience a very, very delightful difference if you go with the dually. Once you've towed with a dully you'll wonder why you didn't make that decision earlier. .... especially long bed, crew cab, diesel! The stability is just ... well ... something you just have to experience yourself to understand.

[Diesel guy]

Originally Posted by scottz

I wouldn't lose any sleep over it; either rear end will be fine. I have the same trailer as you and I have a 4:10 rear axle. It pulls great, but so did my previous Ford with 3:73's. Running 65-70 in 10th gear, I think it turns about 1800. I get 11mpg towing and 13-14 empty; I assume the 3:55 might do a little better.

Get the 4.10s. Your Powerstroke makes max torque at 2000 RPMs on a dyno. The 10 Speed has a .632 10th gear. it will stay in gear towing vice shifting more with 3.55s. My 17 F350 DRW with 4.10s stays in 6th gear. The 6 speed has a .672 6th gear. I run 2050 RPMs at 70 MPH and stay in 6th towing my 41 foot 15700 lb fifth wheel. The 4.10s will tow better then 3.55s

[mlh]

With 10 speeds the ratios are so close together you wouldn’t notice any difference when towing. Where 355 gears might pull in ninth gear for a certain grade and speed the 410s might be in tenth gear but the RPMs will be very close to the same and gas mileage will be the same.
Choose the truck you like.
Lynwood

[bshgto]

I have the 4:10`s, special order in my dually, which really pulls on the mountains and gets on the highway quickly. I wouldn`t have anything else. Screw the fuel mileage.