The limited slip capability of my rear axle seems to be gone. In slippery conditions it just spins one tire - the second never seems to bite.

What's the corrective action for this?

Thanks,

Matt

 

They usually don't work in slippery conditions esp when worn. Best way to check is to get one wheel on sand the other on pave and see if it will lock up. If not there are some options as lockers or a new LS. Some guys have changed oil and modifier to get them to work better. If you are like me it just won't do I had to go lockers. I wanted traction and the LS was useless for any work in the woods or farm , mud etc.

 

If you want to keep the stock setup, you can do a couple things - the first and cheapest is to change the fluid and put in less friction modifier, maybe start w/ none or 1/4-1/2 of recommended amount and keep adding until any "chatter" goes away. That will help if the clutches in the unit aren't completely gone. The second option is to rebuild your unit w/ new clutches - but you'll have the same problem again once they wear out.

A better option is to replace the unit altogether w/ another limited slip, the Detroit TruTrac has a good reputation around here - it's a gear driven LS so there's no clutches to wear out. I'm in the same boat and that's what I'm planning on.

You can put lockers in it, but I'm personally not a fan of auto lockers on mostly street driven or hauling trucks and no one makes a selectable locker for the rear of our trucks.

 

The factory LS isnt that great... i did find after changing my rear diff fluid after only 55k miles with Mobil 1 75w-140, the limited slip actually works most of the time

 

Thanks, all. I have been planning on doing a fluid change anyway, so I'll start there. What's the cost and project size of the other two things suggested - rebuilding the existing clutches or replacing entirely with a different limited slip?

And by "slippery conditions", I was simply talking about going up a grassy hill. One tire spun, the other did nothing. Had to put it in 4 wheel to get up the hill.

 

The fix is a Detroit TruTrac or something along those lines. From new my LSD far from impressed me and it does not have much preload to it. Hopefully getting rid of the stock LSD next year.

 

Replace it with something aftermarket like a detroit.

I dont know what people dont like about the factory LS, it has NEVER given me any problems with 180k on the clock, and always provides power to the wheel with less traction when off road. That said, if mine does go out, I wont replace it with a factory unit because I like lockers or gear driven LSD better.

 

What year is this, what model? This is the Super/Heavy Duty forum. Your profile says 2013 F150 which is neither. What engine does it have, 3.5L V6 Ecoboost, 3.7L V6, 5.0L or 6.2L?

Limited Slip only available with certain packages, I know this cuz I owned a 2011 F150 5.0L 2WD Lariat Super Crew for 21 months.

 

Detroit lockers front and rear would be my choice. Unfortunately I don't play the lottery so it won't happen anytime soon.

 

I don't think my profile says what truck I've got. It's a 2002 F-250 Super Duty. 5.4. The axle is a 4.10 LS.

 

There was another post above mine that has "disappeared" that I was responding to. member with 2013 F150 has two posts, t'other in the 1961/66 forum. I'll go take a look-see, see of that post still exists.

Edit: Other post is also gone, as is the member, must have been a troll, spammer or both. I doubt 'his' 2013 F150 exists, except maybe in his mind.

Only my response was still present, but I edited it out, because without the 's crap info inre to 1965/66 trucks I responded to, no one would know what I was referring to.

 

Now you're onto something!

 

On my 4.10 LS i changed to royal purple which has modifier in it and it works good now.No chatter yet both wheels will spin .My LS never worked probally too much modifier from factory.I too wish i had the money for a locker but wife wanted a house instead of a tricked out truck ,can you believe that!

 

The 09 F-250 SD 4X4 we bought in April still had some original factory warranty left so we checked things out pretty well. We also found that on damp grass or loose gravel our limited slip didn't engage both rear wheels.

I had the local dealer inspect the limited slip clutch packs and they determined that they needed replaced. This after less than 35,000 miles, which seemed a bit premature to me. They ordered, received and installed them in the rear end in conjunction with a re-gear job we were doing from the original 3.73 to a 4.30. Luckily the local dealer was more than willing to work with us by installing the new clutch packs in the differential while I was in the process of installing the new ring & pinions front and rear.

I did the breakin procedure as prescribed by the new ring & pinion manufacturer and put about 1/3 to a 1/2 a bottle of genuine Ford friction modifier in at the 500 mile differential fluid change that is required to maintain enforcement of the ring & pinion manufacturer's warranty.

Just a few weeks ago I was pulling a load of grain to the local elevator I found myself with the right rear on grass and the left rear on pavement. I went to pull away without engaging the FWD and the right rear spun and the left rear wasn't engaged enough to get the load moving. There was a low moaning sound coming from the rear end as the right rear was spinning. Needless to say I only spun the right rear momentarily prior to shifting to FWD which got me moving without much effort.

Given that scenario, in you guys opinions, did I do any damage to the limited slip clutch packs? Also, should I drain the fluid and not put any friction modifier in it at all. This is a work truck that gets used pretty hard and I can tolerate some chatter if it means the limited slip will be stronger when I really need it.

 

They put in to much modifier in the fluid. I would drain and refill diff with out modifier and then slowlly add modifier till it works how you want it.im told you go to empty lot and do figure 8s SLOWLY and listen for chatter slowly addin modifier till it stops chattering. I m not that patient so i justs spent the money on the royal purple which has modifier in it already.