I have an 04 4x4 with a 5.4 and 3.73s. My truck is leveled with 305s which are 33.5" tall and i tow everyday. I'm getting 13ish mpgs mixed driving country/city no highway not towing my work trailer and 10ish pulling the trailer. I was wondering if going to 4.56s if I would get better mpgs towing since the truck would be working less to get up to speed and not have to fight to keep it in OD?

I'm not worried to much about highway mpgs since I've only taken it on one trip in 4 yrs with the truck since I got it. I read before that if you just go up one gear size, 4.10 in my case, its not really worth the expense of re-gearing compared to the benifits gained.

 

Your tires ain't monsters but they're not stock either.....its too bad the 4.30 reverse cut isnt made for the front axel that would be a great hear for the 33"......my gut feeling is that 4.56 is over doing it unless you get 35"....

 

It might be a little better, but 4.56s are pretty deep for only 33s. I doubt you would see enough of an improvement to pay for the gear swap.

I have 4.10s with 33s and get around 14/16. I would think that you'd be about the same... have you had your sparkplugs changed?

 

Yeah I did a tune up at 100k and I have almost 116k on the ticker.

I just figured that 4.56s would move my trailer with way more ease than the 4.10s and be worth the cost of install.

 

1600 in gears can buy alot of gas for a only 1-2mpg improvement.

but i think think it would be similar with me running 35's and 4.88's i get 14mpg on the highway.

 

Yeah but if I have the extra cash and not only getting better mileage, but less strain on the drive train is worth it to me. Just trying to determine if 4.10s or 4.56s would be the better route. don't want to be disappointed with 4.10s...

 

if you dont travel over 60mph often then i would just get the 4.56's

how heavy is the trailer?

i sit at 2K rpms at 60mph with my 35's.

 

It's about 5k. Right now 60mph is almost exactly 1500 rpm

 

I spin about 2000rpm with 31s and 4.10s.

I agree with Str8t Six. If you almost never get on the highway or go over 65mph, then 4.56s will work. They'll provide a huge improvement in towing and acceleration also

 

How much rpms would I be turning at 60 with the 4.10 and 4.56s? If I het a hood deal at my local speed shop I wonder if 4.10s would b more in consideration

 

I don't plan on going bigger than the 305s

 

Calculator

 

according to this calculator
http://www.4wheelparts.com/aux_incl/gear_ratio.html

it says my rpms are at 3045. if you looks at it with 33's and the 4.56's it is about the same.

so your 4.56's and 33's are almost equivilant to my 35's and 4.88's.

how heavy is the trailer you pull?

 

Huh, that's screaming a little bit. On the back roads I drive 60-65 and 3 grand is a bit much. My trailer weights approx 5k.

 

thats out of overdrive. its 2K rpms in OD.