FX4 Locking Differential
Elder User
Joined: Sep 2004
Posts: 560
Likes: 0
so, help me out here, from what Im reading, and from what a friend of mine said, the E-Locker should only be used in REAL off-roading situations? When I use 4X4, 90% of the time its in Michigan snow. So from what my friend had said, he would NOT use an E-Locker in "just snowy" conditions because it would be too rough on the locker. Is this correct?
Posting Guru
Joined: Jan 2008
Posts: 1,048
Likes: 1
From: altoona
i use my locker every time i use 4wd and why because i have it use
drivin in snow it makes no differents and with it locked i've seen no real differents and also if it does affect you in a turn just turn of the **** and done in or out
drivin in snow it makes no differents and with it locked i've seen no real differents and also if it does affect you in a turn just turn of the **** and done in or out
Posting Guru
Joined: Sep 2006
Posts: 1,392
Likes: 1
From: Dayton, TX
a lot of people say its and open and lots say it has a limited slip. i say it has the limited slip because like you i can get both rear tires to spin in 2wd with traction control on (only for a second untill it kicks in) OR off. i have pulled stuff in 2wd on dirt, rocks, and concrete and still got both rear tires to break loose.
Senior User
Joined: Dec 2003
Posts: 212
Likes: 0
From: Spruce Pine, NC
It cannot have both and have the stability managment work. My 09 FX4, is only available with e locker. Some of the 4.6(STX,XL, etc) have a limited slip available, but do not have stability managment. Traction control is a lesser problem, but electronic stability managment has to have each wheel independent of each other. Otherwise when it engages you would go in the ditch - the opposite intended result would occur.
Senior User
Joined: Sep 2004
Posts: 447
Likes: 0
From: Colorado
I still have my window sticker and it says 3.73 LS (limited Slip) and it also says e-locker. My truck is an 09 FX4, So based on my window sticker for the LS and my use of the e-locker I would have to agree with arno on this one.
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC
My 5.4L, 4x4 Lariat has:
3.73LS
ADVANCETRAC WITH ROLL STABILITY CONTROL STABILITY ENHANCEMENT SYSTEM (TCS, ESC, and RSC)
Trailer sway control
3.73LS
ADVANCETRAC WITH ROLL STABILITY CONTROL STABILITY ENHANCEMENT SYSTEM (TCS, ESC, and RSC)
Trailer sway control
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Senior User
Joined: Mar 2004
Posts: 493
Likes: 0
Whalebird you have no arguement. The whole tc, rsc.... Whatever other features work seamlessly with a LSD or the locker. It is right in the owners manual.
I can lay down two strips of rubber in my fx4 with tc on or off. I can do this on snow, wet pavement, mud... The only time a get a wheel to slip is climbing steep off camber hills. Ford does list my truck as having a 3.73ls eld. So all signs point to a limited slip when unlocked.
However, I have seen a blown up diagram of my diff, and there are no
clutches. It is possible that it is a clutchless type of limited slip, or the diagram was wrong, or traction control just kicks ***(even while supposedly off).
I can lay down two strips of rubber in my fx4 with tc on or off. I can do this on snow, wet pavement, mud... The only time a get a wheel to slip is climbing steep off camber hills. Ford does list my truck as having a 3.73ls eld. So all signs point to a limited slip when unlocked.
However, I have seen a blown up diagram of my diff, and there are no
clutches. It is possible that it is a clutchless type of limited slip, or the diagram was wrong, or traction control just kicks ***(even while supposedly off).
Junior User
Joined: Oct 2003
Posts: 74
Likes: 0
Read the stupid owner's manual. I can't believe we are still discussing this:
2009 FX4 Owner's Manual:
Electronic locking differential (ELD) axle (if equipped)
This axle provides added traction on slippery and/or off road surfaces,
particularly when one wheel is on a poor traction surface. In normal
driving conditions the rear axle function as a standard axle. The ELD
may be locked or unlocked by the vehicle operator. Refer to Four-wheel
drive (4WD) operation section in this chapter for further detail on ELD
function and usage. When the axle is unlocked it will function like a
standard rear axle. When the axle is locked it will not allow the rear
wheels to rotate at different speeds when turning. The ELD axle is not
recommended for use on good traction surfaces such as dry pavement.
Doing so may result in abnormal driving behavior while cornering and
excessive tire wear.
Editing just to post that I'm not targeting anybody in particular. But people complain about stuff on a $40K+ truck, yet they do not even read their owner's manual. I also see people think you can't have TC and LS at the same time - that is also not true. LS is an option for all other models other than FX4.
2009 FX4 Owner's Manual:
Electronic locking differential (ELD) axle (if equipped)
This axle provides added traction on slippery and/or off road surfaces,
particularly when one wheel is on a poor traction surface. In normal
driving conditions the rear axle function as a standard axle. The ELD
may be locked or unlocked by the vehicle operator. Refer to Four-wheel
drive (4WD) operation section in this chapter for further detail on ELD
function and usage. When the axle is unlocked it will function like a
standard rear axle. When the axle is locked it will not allow the rear
wheels to rotate at different speeds when turning. The ELD axle is not
recommended for use on good traction surfaces such as dry pavement.
Doing so may result in abnormal driving behavior while cornering and
excessive tire wear.
Editing just to post that I'm not targeting anybody in particular. But people complain about stuff on a $40K+ truck, yet they do not even read their owner's manual. I also see people think you can't have TC and LS at the same time - that is also not true. LS is an option for all other models other than FX4.
Last edited by stormsearch; Dec 14, 2009 at 07:13 PM. Reason: Not targeting anybody in particular
Mountain Pass
Joined: Jun 2006
Posts: 135
Likes: 0
Guys, I'm not trying to stir the pot here but I've looked at my window sticker and even reprinted it from the vincode website and it only says 3.73 electronic locking differential. I genuinely would like to know (and would like to have LS in 2wd) but does anyone's sticker actually say 3.73 limited slip or just 3.73 electronic locking. Mine specifically says under "Standard" and "Functional" - "elec lock diff rr axle" and under "Optional" it says "3.73 electronic lock rr axle..............no charge". That does not, with specificity, say it has a 3.73 LS w/electronic lock. Can someone direct me to a definitive source that it is or even in the owner's manual does it specify this?
Senior User
Joined: Dec 2003
Posts: 212
Likes: 0
From: Spruce Pine, NC
Sorry but I am not trying to argue, but it cannot be both. It is an open diff when unlocked, regardless of the rooster-tail test. The tracion control system demands an open dif. That is the only reason Ford has the e-locker, otherwisw they would be using the clutch type diff they have always used.
Senior User
Joined: Mar 2004
Posts: 493
Likes: 0
Sorry but I am not trying to argue, but it cannot be both. It is an open diff when unlocked, regardless of the rooster-tail test. The tracion control system demands an open dif. That is the only reason Ford has the e-locker, otherwisw they would be using the clutch type diff they have always used.
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC