Does anybody's LS actually work? I went around a corner today and it was wet and I figured I'd have a little fun so I pulled the ole' stroker down into 2nd and matted it and........... 1 tire fire

What is this. My truck has a limited slip according to the tag but it obviously doesn't work too well. my work rig is a 97 explorer and it will always spin both of the tires if it breaks loose Accidentally of course.

 

LS doesn't mean locker. The short story is that it needs a little resistance against one tire to make both tires work for you. On ice or mud, it helps to "feather" the brake pedal slightly. See How Stuff Works for more explanation. Or, Waxy will be along shortly for the full explanation.

Matt

 

I'm well aware of the differences between a limited slip and a locker. I didn't post as much as I should have. My 96 had a limited slip also according to the tag but when I took the cover off to put a chrome one on it looked like a plain old open diff to me. Two spiders and 2 side gears in the carrier. Had my 96 been changed or am I missing something? Behind the side gears there were these little pads that may have been some kind of clutch or friction device of some kind but there were no springs pushing the side gears out against them so how well could they work if that's what they even were.


The 96 was the same way. It wouldn't posi out in situations where every other rig I've owned with OPEN diff's would get sideways.

I guess I'm just asking if anyone here knows how well these stock units really work. Maybe someone who offroads theirs from time to time


Didn't mean to flame nafzimo

Just having a bad day I guess

 

I'll wait for Waxy to wake up & fill you in on the details, but our trucks are notorious for not having the most effective LS units. You're not alone -- as far as the mechanicals inside the diff,

 

There are a lot of people on here that will tell you the stock LS is useless, but so far I've had good luck with mine. One day it didn't seem to be working so good but I just stepped on the break a little and both tires grabbed. I don't know about going around corners and gassing it though, I don't try to do that very often. When it is slick though and I need it it seems to work, saved me a few times from having to lock the hubs in. It's also been suggested here that if you are having problems you might try changing fluid, I believe synthetic is believed to help in some cases.

 

Had to put out a fire at work this AM, so just got around to this.

Thanks for the recommendations guys, I'll just post my standard answer, if you've got more questions after that, I'll try to answer them.

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LIMITED SLIP

Before you tear into your diff., a little explanation of how your limited slip works may change your mind about it being worn out. I can't remember which site I found the info on, but try some of the popular LS aftermarket companies, Auburn, Detroit, ARB, etc... You'll find lots of useful info there. Also, for a real simple explanation of how your LS works, try www.howthingswork.com.

The LS system in your rear diff is actuated by torque, which in turn causes friction on a clutch pack. If the vehicle is stationary, with one rear wheel (especially a dually) spinning, the wheel rotates so freely that there is insufficient torque to activate the LS. Rememeber, it's not a locker, it's a clutch system.

Try the old trick of lightly applying the brakes or parking brakes (doesn't apply braking force to the front axle) to apply some resistance to the free spinning wheel and create sufficient torque to activate the LS.
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On wet pavement, the free spinning wheel may not have had sufficient traction to activate the LS, but it should have.

The Ford LS units are notoriously weak. The best (cheapest) thing you can do is change the rear diff fluid to a good quality synthetic and add the recommended amount of Friction Modifier.

If you've got a fair number of miles on your truck, or you want optimum performance, the LS may need to be rebuilt. Like all clutches, the LS clutches are designed to wear out.

If you go to an experienced tech they can rebuild the unit, and increase the tension/preload on the clutches to improve the function of the LS. However, this does cause increased wear, and therefore decreased lifespan between rebuilds.

Waxy

 

Ok that was informative. Have you ever had one apart and looked inside? My question about my 96 remains. If a tech could adjust tension or preload exactly how would he go about it. There were no springs of any kind. I haven't looked inside my 99 but it seems to work the same anyway.

Question #2

I know on a normal clutch, oil causes them to have too MUCH friction so is it the same with these clutches? Is the friction modifier there to reduce or increase friction? Could one put more or less and increase the effectiveness of the LS that way?

Question #3

If these are clutch type Limited slip units as opposed to torsen style limited slips then they work by pressing the side gears against clutches between them and the carrier (Which is spinning) and create friction to help the side gear spin at the same speed as the carrier. They do this by way of a spring between the side gears. Is it possible that my 96 had this spring removed for some reason prior to my purchasing it? This is why I want to know if somebody who understands this has looked inside one and knows if there is a spring there?

 

If you change your rear end oil and put in half the amount of "friction modifier" it will make a big difference in the limited slip.You might even be able to burn up both tires instead ofleaving those one leggers all over town


2002 F-250 Supercab XLT 4x4 5.4 Auto

 

Now THAT answers one of my questions I'm not real big on the smoke shows but a little sprint car driving in the ole Superduty when you have the road to yourself is ok

 

OK even though thees guys get 50 buck an hours to put these truck togther they are not the sharpest tool in the shed.

My ls did not work I went to the dealer and the swapped the fluid. For the ls to work it takes a special synthetic fluid that has a friction addative it seams that the rocket boys on the line get a little confused at time and put the wrong stuff in. After the fluid change I tried it in the wet grass and nothing then after about 100 miles or so I tried again and all was well.

 

the stock LS unit have the small plates to the outside of the spider gears, thats the clutch pack, it does look VERY similiar to an open diff and is really hard to tell the differance till you look in there and see those little plates, The stock units use no springs and such like the aftermarket units, those springs give constant tension on the pack so there is always some friction even if one wheel is off the ground(probably wouldnt be enough friction) At 14k miles on my truck and a few seperate instances i was fed up, i replaced the unit with an Auburn and the unit continually impresses me, i have yet to be in a situation where only one tire turned, and im always testin the thing. It is truely amazing the performance.
Jetjock16

 

That's exactly what I wanted to know Thanks jetjock. I have been wondering since I had that 96 apart if those little disks were the clutches. Now I know. i also know why the stockers dont' work real well in situations where 1 tire has little to no traction. I wonder if springs from another type would work...

Thanks all for the replies I think that answers my question.

 

An Auburn diff is defininatly the way to go if you a true l/s. I put one in my old F-150 and it was defininatly worth it.






2002 F-250 XLT Supercab 4x4 Auto 5.4...the little engine that couldn't

 

You could also look into the ARB air locker or the new Detroit electric unit. Both offer true lockup.

 

Hey waxy-what is friction modifier?-Where do I get it? How much do I add?. I already have a high quality synth. in the diffs.Thanks