With fuel prices as they are and where their going to be, ive been thinking about swaping my 4:10s for 3:55s or can you even do it?

 

ive had the same thought. it is doable but i don't know how much it would cost. maybe it would be cheaper to put in a gear vendor overdrive, then youcan keep the pulling power of the 4.10's

 

You might find somebody who is willing to trade with you. Its alot of work but it can be done. If you have to pay someone else to do the work though it will take alot of fuel to make it pay off. Many times I hear 4.10 guys claim better MPG than my 3.55's

 

if you find a good deal on new gears let me know as i would like to change my 4.10 for 3.55 also.

 

Before I put my lift on I was getting an average of 16mpg with my 4.10. (But I don't really do a lot of pulling). Now, with the lift/tires, I'm getting around 14.

.02 for comparison....

 

I avg about 15mpg and thats without getting on it but once or twice. if i drive hard say all day, you can kiss 15mpg good-bye. I dont do any towing so im not worried about that aspect. what all do you think u would have to change out?

Anyone want to swap? 4:10s for 3:55s?

 

its posible to swap your gears, about 1000 per axel. or get a set of junk yard axels with the gears you want. i wish i had 3.55's for when im unloaded but i love my 4.10's towing im realy temped to get a gear venders overdrive. but as previously stated it would take alot of gas savings to pay for it.

 

If your running stock tires and wheels it may help you, but in town driving ,stop and go could hurt you. I have 3.55 I am getting rid of going to a 4.30 for towing, But my 3.55 and 35" tires are killing me in stop and go, engine has to rev more just to get moving, 4.30 with tires should be 3.99 when done, be glad to sell you mine but may be ahile before I have time to change them out,cost is about 1000.00 with install kits, and if you have to pay someone to set them up and do the work another 1000.00 so 2000.00 is still alot of diesel. 97 F350 4x4 4" lift A/T,

 

At four bucks a gallon, any increase in MPG will help
I would look into the overdrive that everyone else already suggested.

 

back in the high school days i had a f1 with 308, so i wanted 355s. at my local junk yard of retired vehicles there was a whole axle with 355 ls. im sure it wouldnt have been to bad to buy, it was a pull it ur self yard. but like the morons we were, my frinds and i unhooked it in daylight, and waited till dark, and took it. how dumb we must of looked 3 of us runnin w an axle haha. any how. it didnt take long to swap. 4 u bolts, brake line drive shaft and parkin break cable.

but if 4x4 and you wanna make a worth while investment, the overdrive unit would be a nice add. then u still have the 410s when u need em.

i have 355 in my f2, and summer i get 14 15 usually, but on a highay trip, i was gettin over 18 mpg
also a thing to note. how much fuel would u actually save vs how long it will take to pay off the investment

 

you gotta question their math skills if you know what i mean.. ive heard of people claiming to get like 17-20 with 410's and i personally think its bs. the best ive ever gotten in my truck (with 4.10's) is 14, but its usally around 12. i keep the rpm's down, dont drive like an ***, use cruise control as much as possible, ect. and i still do pretty bad. my buddy is swapping to 3.55's from 4.10s cause soon. he gets the same fuel mielage as me now and im waiting on his swap to see how much better on fuel he does to see if its worth it.


just my 2 cents

-brian

 

alright, so anyone have advice for the overdrive devices? and how would my chip figger into one of these?

 

Talk to RubberDuck and I think Barebackjake. I know RD has one and BBJ may have or had one as well.

 

i had a us gear in my 94.5f450 but it had 4.88's in it. i dont have one in my 97 but i have 4.10's in it and i drive it on the hold on to your butt program 90% of the time and drive like an azz and still get 14mpg, if i can be good and ive tried this for a week or so i can get 18mpg out of it driving to and from work 60mph speed limit. last decent trip i had on the highway i got 16mpg on the highway at 75mph. what kills me is the short trips work is only 7miles away and the 70mph speed limit.

the gear vendors have had alot of troubles especially behind a manual trans, especially if your downshifting to slow down. i have a buddy that had one and he kept breaking his he finally took it out. rubberduck has had his down a time or two but i think its workin well for him. i think if ya tow or haul alot and are harder on your truck the us gear is definately a stouter unit, i never had any problems with the us unit in my truck and had put over 300k miles on it. i typically only ever towed with it and for the most part i got 12mpg with it but that was with 14k behind me. i think the od units just take forever to pay out. a set of used 3.55's would pay out a heck of alot quicker. as long as you get GENIUNE FORD GEARS the 3.55's and the 4.10's setup damn near identical, i regeared my buddys truck and ended up with the same shim sizes that i took out. if ya get gears get the ford ones, genuinegear dont set up worth a crap and are noisy, precisions set up pretty close to the ford ones but have just a bit more noise than ford ones. oh yeah and timken bearings unless ya wanna do it twice!!

 

Mine has 4.10's and I can get 16.9 at tegular interstate driving-65-70 mph. ALTHOUGH I usually drive faster than that. I just did a long haul at 85 mph most of the way and I got a terrible 12 mpg. Food for thought.