Don't get me wrong, I'm not complaining about my gas mileage. I'm definately not driving a truck like this for fuel economy.

 

To elaborate more on what I said through pm.

When I had just the level and 34's my transmission (4.6 2v w/4speed) wouldn't downshift very often when going through a hilly area. Now that I have the 6" lift with the same tires the truck is always downshifting, sometimes all the way to 2nd gear at 65 mph. Common sense tells me it's because the wind is now pushing against all the suspension components on top of trying to push the brick on top of it.

I drive about 40 miles one way to work and its a combination of 55, 60 and 65 mph highway. I average 13mpg, hand calculated. I don't like the idea of a programmer but the ONLY reason I'll purchase one is to adjust for the 4:56 gears that will eventually go in when I go with 36's.

 

Thanks for all the help guys. Ok so on average - talking rough estimate here - what would it cost to re-gear?

 

kinda depends.

the more quality the gear you buy the the price goes up, and labor can vary. i would say roughly 500-700 an axle parts and labor

 

I know absolutely nothing about gears. What brand and ratio would you recommend for the Rancho 4 inch and 295/65/20 (35 x 11.6)? I do alot of in town driving and then highway a couple of times a week and get up to about 70.

 

do you want to pony up for quality or are you looking to get it done cheap?

Superior Gear is the best you can buy, made in america with american steel and the absolute premium of premium.

Yukon is also premium, but not as good as Superior

Nitro, and 10 Factory are decent brands that are cheaper.

 

Sweet thanks! Well with everything..you get what you pay for. So I'll probably look towards the higher end. What ratio do you think would be best for my truck if I go through with the tires and lift? 09 FX4 Super Crew 5.4L , 4" lift, 35s. 4.10 or 4.56?

 

thats honestly a call you need to make for yourself. ford equips the raptors with 4.10's and 35's and still rates them for towing. you'll be higher up in the air with a 4" lift. i would say 4.10's would keep your factory "handling" and 4.56's would give you an increase in performance but at a loss of fuel milage. like i stated previous, the difference between 4.10 and 4.56 is roughly 350RPM in overdrive.

so that said im assuming (this is all with guesswork) with 3.73s you're turning about 1800RPM at 70mph. "34"s would put you at im guessing roughly at 1500RPM at 70mph. jumping to 4.10's would put you at around 1750RPM, 4.56's at 2100RPM.

its your call, i cant help you with that.

 

Well Marshal thanks for your help! I really appreciate it. Now it's a waiting game to see if I'll pull the trigger on the lift and tires and everything. I'd love to but it's just a matter of money. And by the way I saw your thread of "THE BUILD" and I just want to say you've done a great job so far. Your truck is looking great!

 

thanks, i appreciate it. good luck with your own build!

 

I've got a decent calculator written for this:

Tire size Gear ratio RPM
265/70R17 (31.61)/3.73 - 1915
35/3.73 - 1730
35/4.10 - 1901
35/4.56 - 2114

I don't remember if you said what ratio you had, but I can rerun for 3.55 if needed.

 

I just looked on Superior's website and their 4.56 ring & pinion set is only $232, Is this all that is needed to upgrade or do I need to buy seal etc? Does this retain limited slip?

 

Not worth $1500 to change 3.73->4.10. Always at least to "steps" for a gear change, 3.73 to 4.56 or 4.88. If you never go over 70mph, 4.88.

 

you'd need the ring and pinion kit, a master overhaul kit (bearings and bolts) and obviously a lube locker gasket or RTV to seal the diff cover.

the master overhaul kits are roughly the same cost as the gears themselves, and yes it will retain the limited slip.

 

Ok,Thanks.. Does Superior carry all of this stuff or do i need to get it somewhere else? Also, Do I need one of those aftermarket diff cover? What do they do, Like the Mag-Hytec?