Hi guys,

I have an FX4 and really wish that Ford was smart enough to allow the locking diff to be engaged in 2wd as well. Is there any way to achieve this? Or am I stuck with an open diff always in 2wd mode?

Thanks!

 

Yeah good Question...And can the elec. locking diff be installed on a 2wd truck?

 

I am not sure about that... I mean for you without one you can just get an ARB air locker for your rear diff. Would be a lot cheaper than buying a whole new diff from the dealer.

I just wish there was a way to lock the rear in 2wd for those that have the FX4.

 

the reason is because it is true locked diff, no slippage, so if you could lock it up people would either be breaking $h1t, or crashing because they couldn't control the truck under heavy power. it is also the reason even in 4x4 it shuts itself off about 40kph. its meant to be there when you are off road moving slow and need max traction or in sever weather conditions.

what is wrong with open diff in 2wd by the way?

 

Nothing is wrong with it but sometimes off road I don't need 4x4 and it would be nice to just lock up the rear only. I am sure other opportunities would arrise for when it would be nice.

It should be the owner's responsibility whether or not to screw something up IMO. I mean my old Tacoma had the rear locker by a push of the button. I love my Ford much more than the Taco by all means but Toyota didn't seem to think it would be a factor for their buyers.

 

i don't know about the taco but i would guess it was a locking diff with clutches which would allow slippage, so if you did drive on dry roads you would break anything.

if Ford gave the person the option dollars to donuts they would get sued or huge warranty claims. what i would like to see is a hybrid of limited slip with the ELD feature. giving the best of both worlds.

 

Open diff in 2WD sucks. It's a 1 wheel drive vehicle and with the lowest amount of traction getting the power. However...

If you are not on pavement and want the rear axle to lock, Ford provides a driver solution - engage 4WD!

 

Ford should have left the LSD in the FX4's as standard like the previous generation had, just improve it.

 

The 2010 Raptor has the ability to engage in 2WD so there may be some ability to modify the current trucks since the Raptor shares the same ELD. But that is just speculation.

 

I know it it isnt the same but a similar idea. Lots of ranger guys did the "brown wire mod" to allow 2wd low range, it put the transfer case in 4wd low, but did not lock in the hubs IIRC. Might be a similar mod to do the new ELD in the FX4s.

 

no its not power goes to both wheels equally until traction is lost.

 

I am sure someone with a wiring diagram could engage their locker in 2wd. I would try to run my own switch and leave the computer out of it. I would also enjoy that function but would rather not void the warranty at this time.

 

No it is when traction is unequal that it is 1wd. Traction can be lost and spin both wheels remember.

 

From Wiki

One undesirable side effect of a conventional differential is that it can reduce overall torque - the rotational force which propels the vehicle. The amount of torque required to propel the vehicle at any given moment depends on the load at that instant - how heavy the vehicle is, how much drag and friction there is, the gradient of the road, the vehicle's momentum, and so on. For the purpose of this article, we will refer to this amount of torque as the "threshold torque".

The torque applied to each driving roadwheel is a result of the engine and transmission applying a twisting force against the resistance of the traction at that roadwheel. Unless the load is exceptionally high, the engine and transmission can usually supply as much torque as necessary, so the limiting factor is usually the traction under each wheel. It is therefore convenient to define traction as the amount of torque that can be generated between the tire and the road surface, before the wheel starts to slip. If the total traction under all the driven wheels exceeds the threshold torque, the vehicle will be driven forward; if not, then one or more wheels will simply spin.

To illustrate how a differential can limit overall torque, imagine a simple rear-wheel drive vehicle, with one rear roadwheel on asphalt with good grip, and the other on a patch of slippery ice. With the load, gradient, etc., the vehicle requires, say, 2,000 newton metres (1,480 ft·lbf) of torque to move forward (i.e. the threshold torque). Let us further assume that the non-spinning traction on the ice equates to 400 N·m (300 ft·lbf), and the asphalt to 3,000 N·m (2,210 ft·lbf).

If the two roadwheels were driven without a differential, each roadwheel would be supplied with an equal amount of torque, and would push against the road surface as hard as possible. The roadwheel on ice would quickly reach the limit of traction (400 N·m), but would be unable to spin because the other roadwheel has good traction. The traction of the asphalt plus the small extra traction from the ice exceeds the threshold requirement, so the vehicle will be propelled forward.

With a differential, however, as soon as the "ice wheel" reaches 400 N·m, it will start to spin, and then develop less traction ~300 N·m. The planetary gears inside the differential carrier will start to rotate because the "asphalt wheel" encounters greater resistance. Instead of driving the asphalt wheel with more force, the differential will asymmetrically split the total amount of available torque, and will apply a vast majority of torque to the ice wheel to spin faster, and the asphalt wheel will remain stationary, compensating for the stopped wheel by extra speed of the spinning ice wheel. The actual torque on both roadwheels will be the same - limited to the lesser traction of 300 N·m each. Since 600 N·m is less than the required threshold torque of 2000 N·m, the vehicle will not be able to utilise the output from the engine, and will not move.

An observer will simply see one stationary roadwheel on one side of the vehicle, and one spinning roadwheel on the opposite side. It will not be obvious that both wheels are generating the same torque (i.e. both wheels are in fact pushing equally, despite the difference in rotational speed). This has led to a widely held misconception that a vehicle with a differential is really only "one-wheel-drive". In fact, a normal differential always allows the transmission of equal torque to both driven roadwheels; unless it is a specific type of differential, such as locking, torque-biasing, or limited slip type.

driving down straight road equal torque both wheels, when traction is lost the when with least amount of traction spins.

 

...the Traction Control system will also help the open diff.

From the Owners Guide: