looking at an ecoboost couple of questions

APT wrote:

Lessmore wrote:
Over the 10 years I had it...the locker made the whole vehicle slide out in a nano second....on a couple of occasions when I hit unseen glare ice. Those automatic lockers can be lethal in ice country.

Different strokes. I still rather have two wheels driven instead of one in any low traction situation. While that is riskier to lose control of the back end, it also allows a higher level of control and acceleration.

I have a T-shirt from college auto club. "If you can't make the turn, drive sideways"

I don't disagree with you. I prefer to have two wheels driven in a low traction situation too.

But my preference is to be able to control whether the traction device is switched on or off, by the operator of the vehicle.

I remember years ago there was an ARB locker system. I could be wrong but believe you could switch the locker on and off from a switch on the dash.

I like locking drive axles...also limited slip drive axles. But do prefer the action of a locker.

Traction is always good.

Les

I had the 3.73 ELD and it came in handy to get through soft grass without spinning the wheel. My truck had 27000 miles on it and lifetime average was just under 16 MPG not towing, probably 40/60 Hwy/City. For me I had to drive right around 55 MPH to get anything decent like 20+ MPGs.

Lessmore wrote:
Over the 10 years I had it...the locker made the whole vehicle slide out in a nano second....on a couple of occasions when I hit unseen glare ice. Those automatic lockers can be lethal in ice country.

Different strokes. I still rather have two wheels driven instead of one in any low traction situation. While that is riskier to lose control of the back end, it also allows a higher level of control and acceleration.

I have a T-shirt from college auto club. "If you can't make the turn, drive sideways"

Wes Tausend wrote:
...

I can comment on the the electric axle locker only. It certainly won't hurt while towing, or otherwise, and will help if you happen to camp somewhere in dry weather and have to leave by driving through mud after a rain.

The older positrac/traction-lok clutch type axles were a nuisance on icy roads. Since they were engaged all the time, until they wore out their clutches, there was a tendency for the rear to suddenly slip sideways on an icy hill because the tires didn't slip at all until both could slip at once. This "surprise" has spun more than one vehicle into the ditch and I surmise, is the reason that safer, selective, speed de-selected, electric lock is now offered.

One wheel slipping, on non-locked differentials, at least allows good steering tracking and a warning to ease up on the throttle. You will notice that front locking has never been commonly offered OEM and, if you can imagine, is usually recommended against for the horror that can create in winter steering loss. I live in ice country, and owned both a car and truck with the tricky old rear locking systems. To me they weren't worth the repeated white-knuckle ice experience for the very few times I needed them off-road.

Wes
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You are exactly right Wes. I live north of you...similar weather...and I had a truck with a locker axle. Over the 10 years I had it...the locker made the whole vehicle slide out in a nano second....on a couple of occasions when I hit unseen glare ice. Those automatic lockers can be lethal in ice country.

The only locker I would get would be one where I had control of when it was switched on.

Les

My neighbor has one w/3.31s and he tows a cargo trailer w/his trike in it. He's old-school and still thinks they got to have salt flats gears to get good mpg. Guess he doesn't know about double OD yet. Now he wishes it had lower gears. I drove it and I think the 3.31s killed what could have been a much more peppy vehicle. I bet 3.73s would be badass! Craig

We have a 13' XLT, Screw, Ecoboost, HD, 4x4, w/3.73. Gets 20.4-21.7 hiway & 17.8-19.5 city & 9.8-10.6 & as hi as 11.4 towing a 8600# 31' TT. For being a Mickey Mouse so called 1/2 ton ... it an Awesome machine.

...

I can comment on the the electric axle locker only. It certainly won't hurt while towing, or otherwise, and will help if you happen to camp somewhere in dry weather and have to leave by driving through mud after a rain.

The older positrac/traction-lok clutch type axles were a nuisance on icy roads. Since they were engaged all the time, until they wore out their clutches, there was a tendency for the rear to suddenly slip sideways on an icy hill because the tires didn't slip at all until both could slip at once. This "surprise" has spun more than one vehicle into the ditch and I surmise, is the reason that safer, selective, speed de-selected, electric lock is now offered.

One wheel slipping, on non-locked differentials, at least allows good steering tracking and a warning to ease up on the throttle. You will notice that front locking has never been commonly offered OEM and, if you can imagine, is usually recommended against for the horror that can create in winter steering loss. I live in ice country, and owned both a car and truck with the tricky old rear locking systems. To me they weren't worth the repeated white-knuckle ice experience for the very few times I needed them off-road.

Wes
...

Might want to check the payload too. 4k dry TT means 5k loaded, 600-700 pounds of TW. Some of those fancy crew cabs have less than 1200 pounds of payload. Add a family, bed top, steps, etc and a bed full of camping gear and it is easy to exceed GVWR. Just verify the door jam for the Tire and Loading sticker as you shop.

riven1950 wrote:
Thanks for the info. Interesting on the rear end. It seems every one I have looked at has the 3.31 Will that make a big difference over a 3.73? I think my 04 F150 has the 3.73 Since I am looking at leftover 2013 models I don't have the luxury of ordering a specific RE........

Only issue with the 3.31 is low tow capacity. You may want to look for the 3.55 or 3.73 but those are quite rare.

riven1950 wrote:
I am looking at a 2013 f150 ecoboost. For those that may already have one I have a couple of questions.

1- Some trucks have a 3.31 electronic locking rear axle, others have a 3.31 regular axle. Other than cost ( 420.00 ) what is the difference and would it matter towing? The one I am most interested in actually has the electronic locking rear axle.

2-What kind of mileage do you get when not towing ( city / highway / combo )?

I know towing mileage will likely not be good even though I would only be towing about 4000lbs, it is still a box holding me back.

Was real impressed with the power vs the v8.


thanks in advance

I don't tow nearly as much as I used to (personal reasons) but I have approximately 7,000 towing miles on the Ecoboost Truck with my trailer. That's over an almost three year period and previously I would tow twice that much each year.

Since your truck already has a 4X4 option it's not likely you'd have occasion to use the locker when towing. One POSSIBLE exception would be if you get WAY off the beaten path and camp deep in the forest using fire roads etc (I often do that with only a LS rear end).

Towing mileage is not that much better than I got previously with the 5.4 V8. I got about 8.5 to9 9.5 with the V8 and I get right about 10 MPG under most conditions with the Ecoboost (my trailer and travel load is over 10,000 lb). BIG difference is the over all power and the performance at high altitude (no drop off at all). That's an advantage only diesels can match. For what it's worth I almost NEVER go towing in a city so city towing MPG is a "non issue" I HAVE found that the "Miles to empty" feature is accurate enough even with mixed towing/non towing miles that is is actually useful.

Non towing MPG is 'good" but you CAN do better on a couple of different trucks but you sacrifice all that power to do so. If you're buying for towing purposes you will LOVE the ecoboost. I regularly tow up to 8% grades in 4th gear at rated speed limit (that's high gear as fifth and sixth are both OD gears). ON the down side the engine braking is not QUITE as strong as with a big V8 engine but it has never caused a problem, as you simply adjust your driving style to compensate for it. At the bottom of a long downgrade you can easily still lay your hand on my brake discs.

Good luck with your decision / Skip

BTW: 35,000 miles on my truck now and it's had ONE repair (they left a screw loose on one of the intercoolers from the factory which set a "check engine" light. Happened on the way home from picking up the truck and I purchased mine so early that there were no manuals sent to dealers yet so had to wait a day for a factory rep to arrive to trouble shoot this very simple problem. He tightened that screw and it's been smooth sailing ever since :)