Advice on Limited Slip Differential

OP - You are from Wisconsin. How much snow did you get this year ? Are you going to use this truck year round ?

If you have never owned a truck before, then I would suggest to you that there is nothing worse in snow then a 2WD pickup. There is no weight over the rear wheels so they have trouble getting traction - braking and accelerating. And I've seen too many trucks sit and spin, then kick sideways in snow when the light turns green.

In your situation I would want a limited slip rear end as a minimum and I would most likely check the box for 4WD. In other words - get both. Limited slip might just save you one late winter/early spring night when the snow has melted during the day and froze up on the highway after the sun goes down. Could be a real nasty surprise.

As far as pulling a camper, I like having limited slip when trying to get moving on gravel, or slippery grass (rain or dew).

If you are from Wis, you are aware that there is no substitute for a 4X4, not only when towing but at trade in time. Also recall that the "bully" on the playground was the biggest kid. So it goes to say that the bigger trucks make the best "bully" when towing. To much truck won't seem important when that 7500lb trailer, (close to 9000lb when loaded) is pushing you down the far side of the Brooks Mountain Range. Have fun..Arnie

Ford's have three different rear end options:

1.Open rear end where only one wheel has traction

2.Limited-slip rear end that will transfer some power to the non slipping wheel,
requires no driver input (aka..posi-trac, etc)

3. Electronic locking rear end. Operates as a open rear end until the driver manually engages the locking rear end from the dash. When engaged, both wheels turn at the same speed, essentially "locking them" together. There are a few slight differences between 2WD & 4WD regarding when and at what speed the ELD can be engaged and automatically engaged. pg 225 2013 Ford F-150 owner's manual.(locker rear end) REQUIRES DRIVER'S INPUT

My 02 f150 came with limited slip & has been great in slippery conditions, if given a choice id pick to have it & not 4x4 as I have a 4 wheeler made to take off roads. No need to tear something up when there is a better choice. I use to think I needed 4x4 here in Tn ,sold my last 1 about 6 years ago & would never buy another just for the 4x4 .

Fulltimer50 wrote:
Looks like you guys are getting what I was trying to say.
In the good ol days we had posi-traction. Allowed the racer type to burn two strips of rubber.
Now we have Limited Slip Differential LSD that I THINK works differently than posi-traction.
And Locking Differentials that are open until they are turned on.

They all improve traction and "limit the slip" of a spinning wheel.

Limited slip,detroit locker and many others are types of Posi-tractions just depends on maufacturer and what system it uses.Some have clutches some use centrifical levers some use sprags.

Looks like you guys are getting what I was trying to say.
In the good ol days we had posi-traction. Allowed the racer type to burn two strips of rubber.
Now we have Limited Slip Differential LSD that I THINK works differently than posi-traction.
And Locking Differentials that are open until they are turned on.

They all improve traction and "limit the slip" of a spinning wheel.

lakeside013104 wrote:
We have a steep drive at the lake and an F-350 with limited slip diff (LSD). Getting up the drive during winter with icy conditions is not fun, but with LSD, I often times need only flip the switch for LSD and not bother to use 4WD. Works for us.

Lakeside

Ah, my point exactly.. "May help on slippery roads or if you are stuck in the mud".

No help on clear dry roads. Which is of course why they switched it.

JimM68 wrote:

Fulltimer50 wrote:
LSD is not turned on and off with a switch.

AGAIN, That is a totally false statement. Switchable axle lockers are made and available, both factory and aftermarket. I'm mostly familiar with them on Jeeps, but if they exist there, they could exist anywhere.

Punch the button on the dash, the axles lock. Standard on Rubicon model jeeps for many years. available from aftermarket companies such as ARB on almost any vehicle. Unknown by me on most else, but that means nothing as I am not an expert on everything.

It was a true statement a locking rear has a switch an limited slip does not

K3WE wrote:

JimM68 wrote:

Fulltimer50 wrote:
LSD is not turned on and off with a switch.

AGAIN, That is a totally false statement. Switchable axle lockers are made and available, both factory and aftermarket. I'm mostly familiar with them on Jeeps, but if they exist there, they could exist anywhere.

Punch the button on the dash, the axles lock. Standard on Rubicon model jeeps for many years. available from aftermarket companies such as ARB on almost any vehicle. Unknown by me on most else, but that means nothing as I am not an expert on everything.

Ok...perhaps there's a terminology battle of what Webster says words mean versus what "common terminology" means.

For almost all the trucks I've seen, 'a limited slip differential' is a self contained deal that senses big speed differences between the axles and automatically locks out the differential.

Now- a system where you flip a switch and lock the differential...yeah, I guess that's gonna limit the slip a little bit too ;)

...and just because I've never seen such a system on 'typical' trucks doens't mean it doesn't exist and whether the wording "limited slip" vs. "locking" is defined by some sort of standard...I can't say.

That's my understanding also and to me LSDs do not have switches to do anything, they are there as a designed built in capability. They use internal clutches that engage when the slip in one wheel exceeds the other and help engage both wheels. Things like ARBs, et al are lockable where both wheels are tied together in basically a solid manner. A HUGE difference is you can drive in very, very slippery conditions with an LSD, but to do so with a locked differential is a receipe for disaster since you can't control where to steer. Also, you can still get one wheel spinning in slippery conditions with an LSD if the fluid mix is not right or the clutch pack is worn out.

Finally, what is commonly called lockable differentials use clutch packs, but they are activated either by electric or air modes whereas LSD clutches are activated by centrifugal force from the spinning of one wheel like in an open differential.

Larry

K3WE wrote:

JimM68 wrote:

Fulltimer50 wrote:
LSD is not turned on and off with a switch.

AGAIN, That is a totally false statement. Switchable axle lockers are made and available, both factory and aftermarket. I'm mostly familiar with them on Jeeps, but if they exist there, they could exist anywhere.

Punch the button on the dash, the axles lock. Standard on Rubicon model jeeps for many years. available from aftermarket companies such as ARB on almost any vehicle. Unknown by me on most else, but that means nothing as I am not an expert on everything.

Ok...perhaps there's a terminology battle of what Webster says words mean versus what "common terminology" means.

For almost all the trucks I've seen, 'a limited slip differential' is a self contained deal that senses big speed differences between the axles and automatically locks out the differential.

Now- a system where you flip a switch and lock the differential...yeah, I guess that's gonna limit the slip a little bit too ;)

...and just because I've never seen such a system on 'typical' trucks doens't mean it doesn't exist and whether the wording "limited slip" vs. "locking" is defined by some sort of standard...I can't say.

K3W3....I think you got this problem figured out. The wording means different things to different folks. Thank you for clearing things up.

Lakeside