what kind of gas mileage are u guys getting?

[hmadhopper]

i have a 89 f-350 crew cab dually. its a 7.3 with a manual.im building the new motor for it but before it shot craps i was getting pretty poor mileage and with diesel being so high that kinda sucked. i do have 456 rear gears i was told. wich i am with out a doubt going to try and find another rear end.but i was curious what the possibilitys are with mileage. the most i usually pull is a 16ft car trailer.

 

[funnyman06]

Im getting about 17 - 19. Best i have gotten is 22, worst is 12.

 

[97idi]

well i would imagine those gears are great for pulling but your highway drives would be high on the rpms,

i have a 5 speed dually with 4.10s and 33in tires and not loaded i get about 22 hwy taking it easy i just sold my toy hauler and when i pulled it it weighed about 12k and i got about 15mpg sometimes a little less or more never stayed all that consitant.

if your going 4 millage get some 3.73 or 3.55 in that thing although they wont be the best for towing.

how much weight are you pullin?

 

[hmadhopper]

ha yeah it would pull a house down. the people i bought it from did some rodeo stuff and pulled like a 40 ft horse trailer or something. i noticed some people on here running 3.55 gears. i pull a 16ft trailer its a all steal trailer floor and all a heavy equipment trailer.not sure the weight. but its heavy.and usually im have a truck i built on it and i guess it weights about 10k.in the future i would like to get a 2 or 3 car hauler though.

 

[97idi]

well you could always get a gear splitter

 

[hmadhopper]

i was kinda thinking of just putting the 373 in it or 410 and just living with it. but whats involved in doing a gear splitter. and im assuming it is probaly pretty pricey?

 

[97idi]

their like 2 grand i think maby more, or less.
it goes on the end of the trans between it and the transfercase if u have 4x4

 

[hmadhopper]

maybe ill check into that.for now ill see if i can try and find some other rear ends around here with other gears and see if i can get it to wear its good.

 

[97idi]

yeah that might be the way to go
good luck!!

 

[david85]

Keep your cruise RPM at 55 MPH or less and you should be able to manage acceptable fuel economy with or without a trailer. If you can tolerate lower cruise speeds then that, you should be able to just touch 20 MPG.

 

[Uncle Mater]

I would try out the 3.55 or something around there. I also haul a Trail Right 16' all steel enclosed trailer for my work. I will be changing the gearing out cus right now I have a GV unit with a C6 and 4:10 in the rear. Here in San Diego, Ca. if you cannot travel at 65 easily, people will hit you. Right now with all I have, the truck is turning about 3,500 rpm's at 65. I would like to get that lower.

 

[LCAM-01XA]

12 mpg city, right around 20 on long highway runs if I keep at 55 mph. Truck setup is in my signature.

 

[Fordsandguns]

I would try out the 3.55 or something around there. I also haul a Trail Right 16' all steel enclosed trailer for my work. I will be changing the gearing out cus right now I have a GV unit with a C6 and 4:10 in the rear. Here in San Diego, Ca. if you cannot travel at 65 easily, people will hit you. Right now with all I have, the truck is turning about 3,500 rpm's at 65. I would like to get that lower.

That doesn't sound right. 3500 at 65 with a GV? Maybe it's an underdrive instead of overdrive? I haven't driven a truck with a c6 but from everything I've read even with the 4.10s and no GV you shouldn't be at 3500 at 65
Maybe your gears are actually lower than 4.10?.

 

[jim_22]

I just checked my RPM, 4.10 gears and the Z5, it is 1800 RPM at 55 mph in "overdrive", somewhere in the low 2's at 65 mph. It is with the stock tires. When I change tires I am going up a size to 255/same profile, gains 1 1/2 inches, will lower RPM by 5%. My mileage, all highway, averaged over a cross country trip is a consistent 17 mpg at a steady 60 mph, no tow. Starting and stopping the truck for short trips inhales the fuel.

 

[Goofyexponent]

I think I worked it out by order of math one day and got about 19 - 21 MPG with my truck. In Canada, we use the imperial system still for some reason. I worked it out to about 25 MPG imperial empty. When I hauled the trailer around a couple of times with an F150 4x4 and a Ranger 2WD on it, it dropped to about 18 MPG Imperial or 14 -15 MPG standard running at 50 MPH.