I have used my locker 3 times so far. Once at the beach on the sand, once to pull shrubs out of the yard and once when it iced to see how it handled. In 2wd it does one wheel and drive like an open diff. I have spun both in loose gravel but I also one wheel peel in the rain or after washing the truck and turning around in the street. I would like an upfitter switch so I could lock it as needed. I don't know if splicing in a 12 volt switch would cause any PCM issues or not...

 

I really don't know how often my L/S actually benefits my driving, but I don't carry any extra weight in the bed and only use the 4wd after I'm stuck, usually. (or entertainment purposes)

I've driven around during 18" snowfalls and most of the time remained in 2wd.

Other heavy snows, I've driven around for 2 weeks in nothing but 4wd. (13.2 mpg using up 32 gallons of petrol in 4wd)
4.6-3v.

 

The OP brings up a great question. I had been considering buying a F-150 FX4 w/ the 5.0 V8 as a new daily driver / winter vehicle. In Southeast Michigan, we see maybe on average 5-10 days of real snow. The other days are just mixed conditions: dry roads, wet roads, icy conditions, lots of road salt, etc... My current daily driver is a 2000 Crown Vic. When it was stock, it had 3.55s with an open differential. It absolutely sucked in the snow. When I switched to a limited slip differential, using the same tires as before, I was able to actually drive in the snow at a reasonable speed. I am a firm believer in limited slip differentials. My 07 Mustang GT has the stock 31-spline Traction-Lok LSD with the stock carbon fiber clutches, and it too is fun to drive.

However, the Traction Control that Ford likes to advertise as a replacement for a limited slip differential, is pitiful. At speeds below 35 MPH or so, the Traction Control utilizes your ABS to modulate the rear brake(s) to control wheelspin. Upon further demand or above 35 MPH, Traction Control starts to cut out your ignition/spark to reduce engine torque. What this means is if you are stuck in snow/sand/gravel, it will overheat your rear brakes (or at least cause the ECU to think you overheated your brakes and then just disengage Traction Control entirely) and not work at all, leaving you with an open differential until the ECU thinks the rear brakes have cooled.

I obviously see the benefit of the Electronic Locking Rear Diff in a pure off-road environment, you don't want a Locking Rear Diff on normal driving conditions. But I am curious as to how effective the FX4 on the road. It seems to me like in 2WD mode without the rear locked, it is quite similar to the Crown Vic when it was stock: light weight distro in the rear, open differential, etc... except the FX4 is heavier and has more ground clearance with all-terrain tires.

I know what a RWD car feels like in snow with an open rear differential. Is the FX4 the same way in 2WD mode in snow? Would I honestly have to manually select 4WD-H or 4WD-L w/ Locking the Rear Diff if I encounter a deep snow condition where I need to accelerate from a stop? And then switch it back to 2WD after I am through and proceed to speed up and encounter turns/curves?

 

*OLD THREAD ALERT*

Yes. Though there is a mod' using Raptor components to allow E-locking in 2WD.

Maybe YES. Maybe NO. Depends upon the conditions. Usually just 4WD is sufficient.

FoMoCo's recommendation is YES.
.

 

wow, it is an old thread

FWIW - on my 2012 XLT I can lock the rear diff while in 2WD... just pull on the 4WD **** and it locks the rear diff. You have to rotate the **** to put it in 4WD and then you can pull it to lock the diff in 4WD.

From what I understand, the locker disengages as soon as you hit 25 MPH

 

The earlier year 150's cannot lock in 2wd, without modifying the tccm and switch anyway.