I have a 2003 4.6 2wd and its on 35's on 18's im gettin pretty crappy mileage and was wonderin if regearing would help gasmileage at all???

 

What gears do you have now? Highest gearing should be 3.73's, and 4.56's on the "lower" end.
I have factory 3.73 gearing, and I know 4.56 gearing would far better for 35's and keep RPM's good for highway mileage...... or I'd get 4.88's (a stretch for 35's, but if I had 37's or bigger they'd be fine)

 

Depending on what most of your driving style is, gears can help your mileage. More so it will take a load off your engine and trans, not to mention it will be a lil peppier!

Especially since you have a 4.6 i would go 4.56 no doubt.

 

I do 75% city drivin and 25% highway, how much does it usually cost do have it installed and what brands are good ones for the ring and pinion

 

Depending on your local labor rates a gear swap can run $600-$900 per axel.....i use yukon gears but theres other good ones on the market also....

 

Consider replacing both wheel bearings and all seals etc. if your changing the gears. I paid $900 for everything and that included a 500 mile check up and fluid change. There weren't any good street performance shops in my neck of the woods so I brought it to an off-road specialty shop.

 

might as well go 4.88's with that city drivin.

 

Agreed

 

The 4.6 needs all the help it can get - it's a car engine and doesn't have that much low end torque.

 

Did you guys buy the gears first then pay to get them installed?? And did any one see much mpg improvement

 

yes, but you may want to call around first and see what prices are if you provide the gears or if the shop does.

 

You have to keep in mind how much gas 1800 dollars can buy you. If you want the gears then more power to you, but I wouldn't do it strictly for mpg purposes.

 

I re-geared my 02 4.6 4x4 which had factory 3.31:1 and changed it to a 4.10:1
Not sure if it helped with mileage, but I currently am running that gear combo with 285/75-17 tires, and I am getting average 13.8-14.5 city and 16.6-18. mpg highway driving.
I bought the gears and did the install myself.
from the looks of your combo, a 4.56:1 might provide you enough get up and go without sacrificing mileage, and be plenty for you around town.
I would look at some of the online calculators for gear/tire/mph combos to see where you want to be. Randy's ring and pinion website has a nice calculator for that. check out the tire height calculator

http://www.ringpinion.com/Calculators/