Right now i have 4.10 but it is killing me on gas. I never pull anything i just drive i don't know whether to go with 3.73 or 3.55. An are they very hard to install? an i know my speed will be off i have a programmer to fix that problem..

 

Stock tires I'm guessing? What kind of driving do you do more of, city or highway? Are you sure its not something else killing your mileage, what are you getting now?

 

its mostly city ya just stock tires i get about 14 to 15

 

that sounds about right for city... a scangaugeII may help with your driving style and may net another gal or two city... Do a tune up on it lately?

sounds like you have a 3.0L - I'd keep the 4.10's

 

I get 17-18 city with my 3.0/4.10s/32"s

I would do a tune up before a gear change

 

an how do you get 17 -18 even if i keep my foot out
of it i cant get that . i have changed the intake i have an under drive pulley,new plug an wires, an i run an 87oct tune from rogue pref... I know i could get better gas millage because at 70 i am running at 3k

 

I would tune up. Check plugs, wires, clean MAF, clean IAC, check o2 sensors, run some Motorcraft Carb Tune-up or Seafoam through it. That won't cost much at all and should help. With a tuner and pulley you should be getting 20 mpg.

 

So you want to spend $600 +/- to get an extra mpg?
Doesn't make much sense to me, it will take a while to pay off. Try ordering an "economy" tune or something. Most of the trucks run lean from the factory, so when someone writes a tune they enrichen the mixture. It makes it run better but of course you're burning more fuel.
Better yet, spend the $600 on slightly bigger tires to bring down the rpms. Personally I wouldn't re-gear with the 3.0L. There is a reason that truck has 4.10's.

 

seriously.....lower gears are more friendly on gas in the city driving. so....4.10 would be fine.

thing is...you're not putting strain on the engine/making it work harder to get going right now....if you had a higher ratio(like 3.55) you'd be making the engine work harder to get going and driving around town. Sure...you'd get better highway mpg's....but you'd lose city mileage.

and honestly...if you wanted to change your ratio....you are WAYYYY better off money wise if you find a junkyard axle with the gears you want already in it. If you have your current axle regeared, it'll run you a minimum of $400 or so....because installing gears is not a shadetree mechanic job...required lots of specialized tools and good experience to get that contact pattern correct. Some places charge $500 for JUST one axle to regear...and that axle is still in the truck! Get a junkyard axle...or trade axles with another member or something. You can get a junkyard axle for $100-300.....and you'd probably be upgrading to an 8.8" as well.

 

if you have a 3.0 you actually are better off with the lower gearing, that motor makes its power higher in the rpm band than some of the other RBV motors. by lowering the cruising rpm, you will be lugging the motor, making it work harder and use that much more fuel. and it will be a little harder on the clutch on takeoffs. 3,000 rpm at 70? well theres youre problem, dont go 70, above 45 mph wind resistance drasticly affects fuel milage. slow down some and your fuel milage will rise. ive got a vaccum guage in the cab and can monitor engine load, 60 in o/d (5th) it doesnt stay above "12" much. at 55 it maintains "15" pretty good. towing the trailer it rarley gets above "10". as far as fuel milage, my 4.0 ohv with stick and 3.73's 4wd gets 19.5 at very best, 14 / 15 in town and towing the 6x10 box trailer i barely break 13 (mostly due to wind resistance of the tall trailer.) in-town milage is hardly a guage of anything, youre stopped alot, sometimes youre stuck in 2nd or 3rd all the way through town. by the time you spend all the cash nessesary on a gearing change, you could have bought alot of fuel. do check youre tire pressure and tune-up if needed. that would probly be youre best bet for any milage gains.

 

^^thanks dave for pointing that out. get that engine in it's powerband...and she's efficient...no matter what engine is in the truck.


i blame the 13-14 mpg on the skinny pedal on the right...