This is for FX4 owners, the electronic locking rear differential activates while in 4x4. If you are in 2wd and are making a right hand turn or if you launch hard, does the rear peg-leg and just spin the right tire or does it still activate the other wheel. Reason I ask is the Raptors can have the rear locked in with the switch in 2wd whereas the FX4 you have to have it in 4x4, whats the advantage? I mean if the FX4 does engage the other wheel while slipping what would be the purpose of having 2 different setups?

 

It's not intended for on-road use so your 'what if' situation really does not have much bearing. What it is meant for, is off-roading.

The FX4 has an open differential when the locker is not engaged. What the open differential does, is try to equalize the amount of torque to both wheels. If one wheel has less traction, it requires less torque to move. Since the open differential gives an equal amount to both wheels, that would mean the tire WITH traction would be getting almost no torque at all since the system is going off of the wheel that has no traction.

With the locker engaged, both wheels will get the same amount of power and torque, but in correlation to the amount the gas pedal is pushed. It will not limit it based off traction.

The advantage to having this available in 2 wheel drive is for situations that you would not need to be in 4 wheel drive, but would still like the ability to have full power to both wheels. It is a very useable tool to have and if you're driving in 2 wheel drive, it is much more crucial that those 2 wheels have full power all the time since you're not relying on 4 wheels to have contact and power with the ground.

Make sense?

 

Thanks and I understand open and limited slip rear ends. But if your FX4 is in 2wd and you are in rain and make a right hand turn, does the right wheel spin and you get no where like my 99 open rear does, or does it work like a limited slip where when making right hand turns both wheels engage to an extent and the truck will move? I know during a turn the limited slip will use both wheels but not equally because making turns with a differential locked will not turn very nice causing rear end hop and tire scuff

 

huh, I could have sworn the 2010 FX4 acted like a limited-slip when the locker wasn't manually engaged. But after seeing your post I read up on it and it looks like you're right...it acts like an open diff unless manually selected...

Never had any problems of that sort. The 2009s and above also have a traction control system that will kick in to limit wheel slippage

 

sorry, double post

 

Thanks, that is what I was wondering. My 99 is a pain in the butt when trying to move it when it rains. I have alot of power mods done to truck which gives it alot of off idle torque. I live in Colorado where it never seems to rain, but on rainy days its very hard to pull out in traffic with an open rear. I'd hate to buy a new FX4 and have similar problems with pulling out in traffic.

 

I would think all the fancy new traction control systems you wouldnt have a problem. More people with the newer models complain of the traction control cutting power when it feels it loosing traction. Either way I have never had a problem with the above mentioned problem but my truck is the stock 5.4 and has 35's. But to me it sounds like better tires would be of some great help if you can't accelerate at a normal speed on a wet road. That's something I could see happening on a snowy our icy road.

 

I am very happy with mine. I was also worried about one wheeling. I have never one wheeled on rain, sand, or street. It is better than the LSD Ford put in my 05 F250. I only used the locker once for pulling stumps out of the yard. I have never needed it yet on the Colorado trails etc. The stock truck has great traction.

 

I was wondering the same thing and excuse my ignorance but the final answer to this is the FX4 use the locker for 4x4 and uses traction control in 2x4? If that is the case I'm assuming traction control simply cuts power? How does that feel in real world driving. Like starting out in traffic on right turn when wet, etc. I have never had anything but Ford's limited slip rear axles in my trucks which for me having always worked beautifully at boat ramps, wet acceleration, etc. For work I have driven some of Ford's other vehicles with traction control and absolutely hated that feature.

 

I have heard people complaining of the traction control on road but more people complain of it when off road in sand and snow and stuff. Like I said I've never had a problem with it, on or off, of road I just turn it off with the button on the dash (which shuts completely off up to 25mph).

 

How does the traction control work in the Fx4? Does it simply cut engine power or does it work by braking or transferring power from indivudual wheels that are slipping? Also, the tc I've had experience with is very noticeable when it kicks on. Is the Fx4's somewhat seemless?

 

bump

Start reading on page 279 of the 2010 user manual (3rd printing), which can be downloaded from Ford here:

http://www.motorcraftservice.com/?li.../10f12og3e.pdf

Is the traction control noticeable you ask? Yes, very much so. It all depends on which parts of the Traction Control engage, but usually, you'll hear (and feel) the brakes being applied (think ABS noise/rumble), random undercarriage rumbling, and RPM loss. It's really annoying. I can tell you from experience, that even when you press and hold the Traction Control button for >5 seconds (all systems should be off up to 35 MPH) the system will still kick in (though not as soon).

I have almost been hit pulling out of my driveway, in part because of this ridiculous system. Here's what happened: I pulled out of my gravel driveway, wheels slipped a little b/c I had to get into traffic quickly (where I live, the two lane road is back-to-back traffic for 2 hours in the morning...not like I can just wait another 30 seconds for a larger break in traffic), I got onto the road just fine with minimal wheel slip, yet the computer still thought I needed help, so it cut engine power (despite the fact that the wheels were NOT slipping anymore), and people ran up behind me doing >10 over the speed limit. *sigh*

This can be mitigated by pressing and holding the traction control button (for >5 seconds) before I leave the house...which is what I do now. For a supposed safety feature, it's done nothing but put me in tight spots (similarly, it has cut on when in a construction zone with uneven pavement). Perhaps one day, as I drive around a blind curve I'll be able to swerve and miss a huge rock that was just out of sight

http://www.youtube.com/watch?v=w-j1Xsx3EUQ

Mostly, though (with the notable exception of pulling out of my driveway), the traction control does not interfere. It has never kicked on unexpectedly when I was on a smooth road, even when it is raining and making a hard right. The truck keeps traction fairly well by itself when it's on pavement. If I had the chance to buy the truck again, I would.

Just my $0.02

P.S. It appears, from my experiences, that the traction control likes to stay engaged until you lift your foot from the gas pedal.

 

I thought I really wanted the e-locker rear in the new 2011 F150 I plan on getting, but am worried about traction when its off as it seems it is a true open rear diff when off. With the power of the new engines, this could be annoying as the rear wheels would spin and you would get nowhere. I recently saw a 13min video on here where people driving the new F150 with the ecoboost and a 6,500 pound trailer in the rain were bragging at all the power because the wheels would spin while trying to accelerate...

Anyone who has ever had a high torque vehicle will tell you how pitiful it feels to not be able to accelerate on wet pavement... in my Mustang which has high torque at a low RPM, I can't keep up with Geo Metros from a stoplight because the wheels just spin, even after many traction upgrades and 2 inch wider tires on the rear than stock. Hmmm, any insight... Don't want to have to run in 4 wheel drive on pavement while towing just because the roads are wet.

 

Yes, it is a true open diff when not locked. To be locked, it has to be in 4hi and under 25mph. If over 25mph, it unlocks and reverts back to an open.

 

Interesting... for a truck driven on the street 95% of the time, I think I would be better off with a limited slip rear end then and not having the e-locker. Any reason this is incorrect?