I was planning on ordering my 2005 crewcab 4X4 dually with the 3.73 axle ratio since I only tow my 11,000# fifth wheel approx. 1000 miles a year. The rest of the time I am either empty or a light 4,000# trailer (occassionally). My only concern is I can't find a dually to test drive that has 3.73's, they all have 4.10's at my area dealerships. The 4.10's went down the highway taching 2,500RPM's at 70 MPH. How would the fuel mileage differ from the 3.73's to the 4.10's and would it be a dog towing with the 3.73's?
PS The truck I just sold was a 2002 F350 SRW with the 7.3PSD and 3.73's and it towed fine for me. I just don't know if the dually will make a difference.

 

dually's will give you peace of mind in case of rear tire blowout with the fifth wheel attached. also makes it a little more stabile when towing. sound like you don't pull that fifth enough to warrent spending the extra money and greif(dealing with extra width) of having duals. good thing you are buying a 4x4, empty duallys don't drive well in snow.
IMO, I would stick with a F-350 SRW 4X4 6.0l 3.73 limited slip.
don't forget to order the Tow Command package and upfitter switches, they are options not standard equip.

 

I would stay with 4:10 all of the figuring I have done and the need...IMO to keep this engine above 2350, you really push the pedal a lot to keep it going at highway speeds if you drop below 2300, 4:30 is too much ...again just IMO, my next truck will have 4:10 in it.

 

Why would you want to keep the engine RPM above 2300? I thought you got your best fuel mileage if you kept it at 2000 or below. As far as why I'm chosing a DRW over a SWR, here are the reasons;

1) I like the way the DRW looks
2) I don't drive the truck everyday. I only drive it when I want to.
3) I have a sickness of not leaving the trucks stock. I want ride quality this time around and if I bought a SRW, lift kit and new sneakers would be soon to follow.
4) Here in the lovely state of Massachusetts, any vehicle with a GVW of 10,000#'s or more require commercial tags and commercial insurance, so if I need to spend that extra money, I my as well get the big boy. I coulnd't even buy a SRW F250 and register it with passanger plates anyone. I think Ford really screwed up when they upped the GVW's over 10,000#'s on the SRW F250 and F350. If they werent over 10,000#'s, I would buy a SRW and save the extra $400/year for insurance and commercial plates but since I can't, it don't matter much.

 

The reality of this is my year long test that I have conducted with my own rig....now I do not care about math and all, I care about what is known, Every year I have the opportunity to travel 12k worth of miles on the same roads over the same terrain twice…so it allows me to run different scenarios with enough mileage to know the difference.

With 3:73 (knowing you have less mechanical advantage then 4:10’s) the 6.0 gets better MPG at 2450 to 2550 then it does at 2300 and below…this I know.... for MY truck and MY style of driving….operative words here MY style….I only use TH when stopping and when I want to keep my RPM’s up….I am extremely gentle on the throttle when pulling no sudden sprits, I keep my EGTS at 1250 all the time, or at least as much as I can. I have done the math and know what the numbers show, I do care about the math, the problem with paper, it cannot figure in passing, head wind, side wind, having to pee, stopping for fuel, stopping to pee, getting coffee, stopping to pee….did I mention…drivers climbing hills that don’t need to keep their momentum up, O-forgot the 45mph construction zones for thirty miles, rain knocks the stuffing out of MPG, did I mention the peeing….that is why the real world test….........at some point rubber meets the road and you must push the loud pedal, to get to....the then next fuel stop…just my thoughts

I did All of these test with a V-10 also….

 

IMHO I suggest the 3.73's. I had a 96 Dodge with 3.55's and pulled a 12,000# trailer. I found it generally satisfactory with the exception of long grades. But there is a HUGE difference between that truck and your 2005. The higher rear and extra power will be plenty for your trailer as long as you can live with the fact that you won't always be the first one up the hill.

Go for the dualies as well. I had a rear tire blow out on me on a motorhome one time. Thanks to the duals I was able to limp into a service station. I've respect my duals ever since. I believe you can't have enough rubber on the road where safety is concerned.

 

Tim, you are really showing your age now . You know there is medication nowadays that help spastic bladder problems .

My 2 cents is get the 4:10. The 3.73 may help the wear of higher RPM on the engine and may even help the MPG situation, but the strain of rolling 4 tires.... I'll let the expert handle that one.

Claude

 

Tim,

So you say that the 4.10's will get better fuel mileage in the real world. I was wondering why I couldn't find any 3.73's with duallies to test drive, they are all 4.10's. I really appreciate your input so here is my driving style. 30% back roads under 55MPH or city driving, 70% highway between 70 and 80 MPH. Like I said, approx.1000 miles a year towing a 11,000# fifthwheel mostly in hilly New Hampshire but not much towing mileage. I probably only put 12,000 miles a year on my truck if that. So, what would be the difference in fuel mileage for me. I know that both ratios will pull what I need to pull. I'm just use to seeing my tach at 2,000RPM's at 70 and not 2,250.

 

One point I forgot to add is geographical location....IMO that also makes a difference on MPG...i.e. mountains vs. open plains vs. traffic vs...I still believe that if I would have ordered 4:10 in my X when I bought it...my MPG would be up…using the vehicle the way I do. I do not drive my truck without the trailer hooked up...important point I needed to make.

The mechanical advantage, starting off form a stop sigh far out weights the disadvantage at high way speeds....again just my thoughts….

 

One more question Tim, the other day I test drove two Cummins power Dodge Rams but then I woke up. Anyway, they both had 3.73's but one was a SRW and one was a DRW. The DRW always seemed to need more pedal to maintain speed down the highway and the SRW didn't. I assume this is due to the drag of the DRW's. Anyway, if I was to choose the 3.73's in the Ford, do you think it would feel like that? I know the DRW I tested with the 4.10's went down the highway effortlessly. If this is the case, I will definitely be ordering the 4.10's. I just wish I could find a dealer in my area with 3.73's DRW to test drive and confirm this theory.

 

My personal experience says............by the way it is my butt that felt this, the 4:10 seems to feel like you are pressing the gas pedal less to move the same amount of weight down the road. Now for the dodge,...weird... did they have the same ration, I would bet not....just a guess on my part...as for the frontal area affecting the feel in the pedal.. probably not.

 

Yes, they both had 3.73's. I check the window stickers on both. Do you think the F350 DRW will feel like that if I got 3.73's? What is the best RPM that the 6.0 PSD likes to run at down the highway? What do you think the actual difference in empty highway MPG at betwen 70 and 80 with these different ratios?

 

Tuff questions to answer, to many variables for a good answer on MPG...IMO... not enough to worry about not getting the 4:10...did both Dodges have exactly the same equipment, did they have the same mileage on the odometer

Again how much towing are you going to do...percentage of overall driving?

 

The mileage was within 30 miles. Both were new. I just don't want to make the wrong decision. I don't mind loosing 1 MPG to get the feeling of rolling down the highway effortlessly but I don't want the motor to be screaming at 80 MPH either. I just want as much input as I can get from dually 4X4 owners. I've searched ford's inventory online and called dealers, there are no duallies around with 3.73's. All are 4.10's

 

I think the reason for that is ...most will be used for pulling big loads....at least it makes sence...can you do a test drive...run home grab the trailer and go aroung the block...