ChucksOliver77 or others---axle ratio questions

8N'r--WI · Dec 23, 2011

What axle ratio is on your F150----I know the recommended ratio depends on what other options are added to the truck.

The truck I have "built" on the Ford Website has the Ecoboost engine, 4x4, automatic, Crew cab, and "defaults" to the 3.31 Non-Limited Slip Axle.

A truck that is available to me has all of the above with a 3.73 Ratio Limited Slip Axle, and is an "extra" option for another $400.

Will a higher numbered ratio (3.73) mean a lower gear, faster pickup, lower top-end speed, and lower gas mileage?

What are the differences in Limited and Non Limited Slip Axles?

...any help will be appreciated.

Tim

Allan in NE · Dec 23, 2011

Do they give you a choice of a 3:55?

I'd think that the 3:31 is a little shallow for a gasser and the 3:73 might be gettin' a bit too deep.

I know that they won't marry a 3:31 and the towing package together.

Non limited slip is just a plain jane differential. Limited slip has the mechanics to make that 'slippin' wheel grab.

Allan

Chris(WA) · Dec 23, 2011

A 3.73 ratio rear end will give you all the things you listed as well as better towing/ hauling ability.
Limited slip locks the differential in slippery conditions allowing both wheels on that axle to pull together. Non will allow one wheel to spin while the other remains still.
This is the set up I have in my 2000 F-150. Works great for me as the truck is used almost exclusively for hauling or towing. If it was a commuter truck I would stay with the high ratio for a little better fuel mileage.

chucksoliver77 · Dec 23, 2011

tim, mine has the 3.73 rear. i think if you live in the hills like i do you may get a little better mileage with the 3.73. the top speed will be the same,as it is governed, but you most likely get there quicker. with the open rear one wheel will spin where as with the limited slip both wheels will drive instead of one if you are in a tough spot. chuck

ASEguy · Dec 23, 2011

The 3.31's are considered "highway gears" because they would allow lower engine RPM on the highway. This was especially important when we had three speed automatics. 373's are better for lower end pulling and may sacrifice some fuel economy at higher RPM's. Limited slip means both rear axles are locked together unless you turn the vehicle. Since the rear wheels cannot go around the turn at the same speed, the outer wheel must spin faster so the pressure "unlocks" the clutches to allow for a limited slip which depends on the degree of the turn. Turning into a driveway virtually unlocks the clutches and driving on a highway cloverleaf allows for less slippage. Open differentials do not have this locking feature and therefore only one wheel spins by design. Hope this helps. Gerard

ss55 · Dec 23, 2011

By "available" do you mean it's already on a dealer's lot? Dealers used to get a 3 percent discount off the list price on the vehicles they ordered for their lot. That was done to offset the cost of carrying expensive inventory. If that is still done the dealer's discount would be $750 off a $25,000 list truck.

There's enough negotiating room there that you should be able to buy the "available" truck for about the same money as than the one you want to "custom order" with a $400 lower list price, but you don't get to pick the color.

The only time a limited slip differential might be a handicap is on a glare-ice hill that a regular differential wouldn't climb. In 2WD the limited slip rear end can fishtail unexpectedly when both rear wheels spin-out together, BTDT. 4WD may handle differently.

Will the website calculate the mileage for the two axle ratios?

MarkB_MI · Dec 23, 2011

3.31 is a fairly tall axle, depending on the tire size. 3.73 is probably a better choice. In theory it will give poorer fuel economy than the 3.31, but in practice you probably won't see any difference.

I will not purchase a pickup without a limited slip differential. A 2WD without LSD is really one-wheel drive. A 4WD without LSD is really 2WD. A 4WD pickup with an LSD in the rear gets you to "three-wheel drive", which is probably good enough. (And if it isn't, you can buy an aftermarket locking differential for the front for serious off-roading.)

ss55 · Dec 23, 2011

By "available" do you mean it's already on a dealer's lot? Dealers used to get a 3 percent discount off the list price on the vehicles they ordered for their lot. That was done to offset the cost of carrying expensive inventory. If that is still done the dealer's discount would be $750 off a $25,000 list truck.

There's enough negotiating room there that you should be able to buy the "available" truck for about the same money as than the one you want to "custom order" with a $400 lower list price, but you don't get to pick the color.

The only time a limited slip differential might be a handicap is on a glare-ice hill that a regular differential wouldn't climb. In 2WD the limited slip rear end can fishtail unexpectedly when both rear wheels spin-out together, BTDT. 4WD may handle differently.

Will the website calculate the mileage for the two axle ratios?

RLA · Dec 23, 2011

1st of all is it hilly where you live & will
you need the power for pulling? If so it"s a
good ratio for you.

If you live in flat country & your not going to
need that power, stick with a 3:31

Throop · Dec 23, 2011

(quoted from post at 07:20:46 12/23/11) Do they give you a choice of a 3:55?

I'd think that the 3:31 is a little shallow for a gasser and the 3:73 might be gettin' a bit too deep.

I know that they won't marry a 3:31 and the towing package together.

Non limited slip is just a plain jane differential. Limited slip has the mechanics to make that 'slippin' wheel grab.

Allan

I am with Allen, my last 2 F-150's have been 3.55 limited slip slips, I figured they were in the middle of the 3.31 and 3.73, my truck is empty most of the time. Maybe if it was loaded more 3.73 would have been a better option.

8N'r--WI · Dec 23, 2011

Allen---they do give you a 3.55 choice, but then recommend the V-8 vs. the Ecoboost.

Thanks for the reply.

Tim

8N'r--WI · Dec 23, 2011

rla----yes, the truck will be used in very hilly country for the most part..in addition to normal use, it will occasionally be used to pull a 31 foot travel trailor and haul small tractors around..

Tim

8N'r--WI · Dec 23, 2011

Yes, it is one of the few left on lots within 1 hour of me....2011 model with 3 packages of "extras" I really don"t need, like the chrome, etc.

I can get it for 20% off list, less tradein, plus tax,license, etc.

Pricing a new one w/o all the chrome, etc. is $1000 more. I didn"t see mileage calculator on the site.

Tim

Allan in NE · Dec 23, 2011

With a half ton?

Oh man! :>(

Allan

Allan in NE · Dec 23, 2011

With a half ton?

Oh man! :>(

Allan

Anonymous-0 · Dec 23, 2011

Mark---sounds like I got lucky with the 3.73....from all the responses, it seems this is what ratio I would have ordered if getting a 2012.

Thanks, Tim

8N'r--WI · Dec 23, 2011

It helps a lot....thanks, Tim

8N'r--WI · Dec 23, 2011

It helps a lot....thanks, Tim

8N'r--WI · Dec 23, 2011

Yes---from the shed in Spring, 3/4 of a mile to park it on the other side of the farm and back again in Winter.

Tim

Traditional Farmer · Dec 23, 2011

You need a 3/4 ton with a 4:10 rear

8N'r--WI · Dec 23, 2011

Sound good to me....I will be using it for about a year for very light duty use, and after I retire and move to the farm, it will be kept there and not used much for over the road traveling....the only trucks I have owned were ones I used when I was in the carpenter business.

1/2 Chevy, 1/2 Ton Ford, and a 3/4 Ton Ford. All very inexpensive models...

Thanks, Tim

8N'r--WI · Dec 23, 2011

Thanks much---truck will be used primarily to commute for about a year, and then retired with me up to the farm...

What do you haul/tow with your F150?

Thanks, Tim

Allan in NE · Dec 23, 2011

Aw-Ha!

That works. :>)

Allan

ss55 · Dec 23, 2011

(quoted from post at 14:16:00 12/23/11) Yes, it is one of the few left on lots within 1 hour of me....2011 model with 3 packages of "extras" I really don"t need, like the chrome, etc.

I can get it for 20% off list, less tradein, plus tax,license, etc.

Pricing a new one w/o all the chrome, etc. is $1000 more. I didn"t see mileage calculator on the site.

Tim

The dealers get a substancial rebate on their model year carry-overs. The dealer should discount a 2011 more than 20% off list, 25% to 30% off would not be out of line . 2012's have been out for about 3 months now. 2011's are all depreciated as a year old already. Your banker and your insurance agent will both value a new 2011 much lower than a new 2012, maybe $4000 less.

NADA www.nadaguides.com and Kelley Blue Book www.kbb.com are a little optimistic on their prices. Edmunds www.edmunds.com has been more realistic on used vehicle values.

I can't comment is a 1/2 ton or 3/4 ton fit your needs.

Good luck.

Chris(WA) · Dec 23, 2011

Might haul most anything. A quad or pulling garden tractor mostly.
I pull a 24 ft. two axle flatbed with a tractor on it often. Also a 24ft. travel trailer. Smaller trailers on occasion.
Truck also has an aftermarket sway bar and air bags. 3/4 tons be damned. I tow within or at its max rated capacity and it works great.
It also drives like a car when its empty.I often say it is the nicest CAR I have ever owned.

Fordfarmer · Dec 23, 2011

You've gotten a bunch of replies, but I'll throw my 2 cents in as well. I'd avoid the 3.31's - those are highway, flat-land gears, and I've seen your part of the state. 3.55's would probably be OK (certainly better than 3.31's) and 3.73's better yet. I have 3.73's in my F350. With overdrive, it's spinning about 1700 rpm at 55. (will depend on tire size, though) With the torque the Ecoboost makes, 3.55's might do you OK, but I'd lean toward the 3.73's. And a limited slip.

barnE · Dec 23, 2011

When you say low or high you gotta specify gearin g or numerically. Low number=higher gearing. Higher number=lower gearing. Dave

chucksoliver77 · Dec 23, 2011

tim, heres some more info on my truck, the engine makes its max torque at 2500rpm with 90% available at 1700 and still at 5500rpm. it has a 6 speed trans with a low 1st gear, at 4000rpm it is only going 25mph. both 5th and 6th gears are overdrives and at 70mph in 6th it is turning about 1850rpm which is at more than 90% of peak torque, which is nearly ideal for cruising. hope this helps clear up some things about this new truck, chuck

8N'r--WI · Dec 24, 2011

Thanks for the Xtra info.....Merry Xmas to you and yours!!

Tim

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