OK, heres the scenario..... BIG snowstorm a few weeks back and my dad brought his 07 F250 FX4 over with the Fisher 8ft VPlow to plow my driveway mess.

Anyways, the plow rode up on the snow he was plowing and then went up onto my grass mound aka my "loading dock" (for bed access).

I hooked my 08 F250 XLT 4x4 with 3.73 Limited Slip gears up to his truck and tried to pull him out/off the mound. First I tried 4x4 Low hooked up front to back and then back to back. Tried 4x4 HIGH......I locked the hubs in manually (auto hubs)....

What I got was 2 wheels spinning and 2 not - ALL the time... and it did NOT go back and forth it just kept tryin to dig itself into the ground. The F'ed up thing is that it was always the ones on the right or the left, never one right side and one left.

I dont get it... wtf is LS for and what is it SUPPOSED to do?

I'm about to say F it and get a manual locker front and back.

I need a truck that will be able to go into the mud this summer and bring wood out (of the woods, derr lol). Theres no way Im gonna take it in with "2 wheel drive" lol.

I KNOW that the limited isnt anything like a locker and that it should transfer power to the wheel that isnt slipping....but my f140 3.73 LS would light both back tires up on pavement, ice, dirt etc any time and it was always both tires- never going back and forth.

Bottom line: Define limited slip. Tell me how it SHOULD behave and why only 2 wheels had power. Cuz im really confused... is my ***** broke, or is it just a horrible design?

Side note: my dad now works for Toyota (come on, no toyota flames - its my dad not me lol), he has an FJ Cruiser as a demo vehicle right now...It has a manual locking rear differential and what they call A Trac where all 4 wheels lock in at the push of a button and all have the ame exact power and turn 100% simultaneouly. There is also the 4x4 lever... so you'd put it in 4x4, click rear diff lock and click A Trac and you can go anywhere....but not haul anything lol. Point being, why do the crappy vehicles have the good features? Ford needs the option for a set of lockers...




Roger

 

This might help explain:

http://en.wikipedia.org/wiki/Limited_slip_differential

The Ford design is better than the open differential, but not by much really.

I will probably switch to a Detroit TrueTrac® someday...

 

Although this isn't an answer to your question, I thought it would help give perspective:
The only difference between a 2WD and a 4WD is that the 4WD will get stuck further up the trail.

 

As you've (hopefully) seen, a limited slip differential will help get power to the ground by limiting the slip of the wheel with the least traction. An open diff just sends power to the wheel with the least traction. That said, LS doesn't mean you'll have enough traction in certain instances. In the example you mentioned, even front, rear and center locking diffs might not have been enough to get him out if he was really in there. Another important thing to remember is that you only have a LS rear diff. The front is open. That said, you're generally better off hooking the tow strap to the rear of your truck.

So does this mean your truck will get stuck on your next adventure? Maybe, maybe not. LS works reasonably well for most folks most of the time. Lockers work great in extreme situations, but are horrible out on pavement. Pick your poison.

 

Once this winter, I was on about a half foot of snow that was on some grass, not pavement, & was parked on a incline. I started up my truck after sitting for a 8 hour shift at work, put it in drive, the rear tire started spinning, a second latter the limited slip kicked in, & both rear tires were spinning, I did however get out without shifting into 4-WD! Limited slip is cool & works well! Plus I loved the two tire patch I left!........

 

Ok, well...let me ask this...

Is LS supposed to kick both wheels in at once like risupercrewman was saying?

I thought its supposed to give power to the wheel with better traction?

Furthermore, if it NEVER tries the left rear tire for slippage and keeps spinning the rear right...how is it suppossed to know what one has the traction?

On FLAT ground in the dirt I can drop the clutch and both rear tires spin. If I do it slow the one spins then the other. However in the snow or at a slight tilt it seems to stay on one side and never try the other.

I wish it would just spin one wheel then lock them both in.... G's

2stroked - As far as the front vs rear goes... if the rear gets pulled off the ground from the chain hooked to the other truck it does no good.... its too light... so then hooking up to the front seems like a better idea IMO... but maybe im wrong.

2nd... my ford bronco as just LS and all 4 wheels had power all the time....i could spin them all on ANY surface at any time... I miss it alot.

Roger

 

Roger,

While I'm by no means the expert on limited slip (perhaps somebody else will chime in), I can offer some thoughts. Limited slip is pretty much just what it says. It's a means to limit the slip between wheels on a given axle. A locker locks the wheels so they both move the exact same amount. An open differential kind of lazily sends power to the easiest place.

That said, LS has some "issues." Since it's a clutch system - and clutches wear and have adjustment - sometimes it's more or less effective. It all depends on how well it's set up and how much everything has worn. Like I noted earlier, for most folks, LS is a pretty decent option because it requires no driver input. A locker is great, but some folks will forget to activate it or turn it off - both being problems.

If you want my 2 cents for trycks driven mainly on the street and occasionally off road, tires make a far greater difference in traction - for less money. My OEM General Ameritrash tires were beyond worthless in the snow - even with an LR rear. A new set of Revos made it a monster in the snow.

 

X2

 

Yah, I know.... tires ARE next.... Im hoping to cram some 35x12.5's in it stock....

I still think LS needs to be redone. If one tire is on dry pavement and the other is on Ice and the one on ice is just spinning...what good is that? It should xfer to the one on the dry...

I just h8 LS I guess, lol.

Roger

 

I think there is no way I'd live without LS on my F150. It provides better traction during the winter having both wheels getting the torque.

 

Yah, IF both wheels ever get the torque. If the one tire spins and it doesnt ever xfer the power ...then what?

The LS doesnt always do what its supposed to....