Thread: Limited Slip Diff

Can Someone explain to me how exactly a limited Slip Diff works.
Here is the senario.
I'm in 2 wheel drive [ surf] and I go over a slight rise on such an angle where the two front wheels are on the road, the left hand back wheel is firmly on the ground [ the front of the truck is facing down slightly] but the rear right wheel is supended in mid air.
I go nowhere.
The rear left wheel just spins.
Now I thought a LSD was supposed to send the power to the wheel with the most grip,to enable you to get out of situation such as this, which it didn't .So what it the point?
Am I missing something here.
I know I have an LSD because it is written on the diff.

They get worn & you are probably asking too much from it, that is what Diff locks are for & broken axles :grin:

The other thing to do is check it has an LSD... nuggets get changed & are easily broken.

Jack the rear up under the diff & spin a rear wheel by hand & if it is LSD both wheels will turn in the same direction.

Thanks.

Its prob an unlimited slip diff now - they do wear out.
You can take apart and add another shim which will put some more life into it

Actually I buggered that up in my description.
I ment, the rear left wheel is firmly planted , as is the two front ones, the right rear is the one in mid air and the one that is spinning
does this make any difference to the replies,? ta
I cannot edit the original post.

Hey mate as said they wear out, What we have found on a couple of trucks is you need to get the speed up in the diff to get any action, Try wacking it in a higher gear and giving it some herbs if you are stuck in this situation and it should send some power to the grounded wheel.

Disclaimer: I am 90% sure this is a good way to fuck all sorts of components in your truck, The alternative is get the LSD reconditioned and it will work all the time.

Originally Posted by jakewire

Actually I buggered that up in my description.
I ment, the rear left wheel is firmly planted , as is the two front ones, the right rear is the one in mid air and the one that is spinning
does this make any difference to the replies,? ta
I cannot edit the original post.

There are variose types of LSD Toyota use a clutch pack type that basicly lightly locks the two sides together under spring tension and locks up harder and harder the more touque is put threw the diff.So when one wheel is lightly loaded or in the air you cant put much if any tourqe to lock it up. a viscous or cone type would be better in this situation as lock up and tourqe transfer to the other wheel is speed differnce dependant.
So to try and over come this .Stop and take off with the hand brake applied firmly,the extra tourqe required to turn the wheels force the side gears in the nugget out against the clutch packs locking the diff up tighter(but not actually locking it in a mecanical sense)
Jack both rear wheels up off the ground in gear hand brake off. Try to spin a wheel if it turns easily and the oppisit turns the other way. You either have a plain old open diff or a very very worn lsd.if its hard to turn for a start then loosens up to easy you have a worn lsd.If its very difficult start to turn then eases up to a bit of resistance its a good one.
Lots of LSDs perform poorly or not at all because they have had regular diff oil put in them.If with the obove checks show you do indeed have a LSD change the oil with proper LSD oil and do it again a week or two later. This will certainly improve it even if it is worn.
Otherwise there is one under my bench I could shim up tight as fuc for ya and you would just have to get someone to fit the ringgear and set backlash for ya if your not confident doing it yourself.

Thankyou for that Vietnamcam, I'll check your suggestions and report back.
I should have a LSD as it is written on it, but whether the correct oil has been put in ???, I'll try that after the checks .
cheers

Georgetown, cheers, I think I'll do the above before first after reading yopur disclaimer:zomg:

I just put that so if it did fuck your truck you wouldnt blame me! My mates SR5 hilux will only spin both wheels in at least low ratio 2nd and 3000rpm, we have been using that method to get unstuck for years and havent broken anything yet touch wood.

Originally Posted by jakewire

Can Someone explain to me how exactly a limited Slip Diff works.
Here is the senario.
I'm in 2 wheel drive [ surf] and I go over a slight rise on such an angle where the two front wheels are on the road, the left hand back wheel is firmly on the ground [ the front of the truck is facing down slightly] but the rear right wheel is supended in mid air.
I go nowhere.
The rear left wheel just spins.
Now I thought a LSD was supposed to send the power to the wheel with the most grip,to enable you to get out of situation such as this, which it didn't .So what it the point?
Am I missing something here.
I know I have an LSD because it is written on the diff.

Jake - your understanding of LSD is a bit out. Read this first:
http://en.wikipedia.org/wiki/Differe...ical_device%29 it should help

Ok, so effectively that is saying in the lsd part, that I should have done exactly what Georgetown suggested and applied more acceleration untill the LSD came in to play.[ if indeed it is not buggered or that the wrong oil is in there]

Originally Posted by jakewire

Ok, so effectively that is saying in the lsd part, that I should have done exactly what Georgetown suggested and applied more acceleration untill the LSD came in to play.[ if indeed it is not buggered or that the wrong oil is in there]

Yes and no. More wheelspin will transfer a bit more torque as friction between the plates increases,a short burst of welli wont hurt it but full noise in say high 3rd and not going anywhere will burn the fiber plates and glaze the steel.
Rideing the brake can be very effective(especially with a front lsd also) as the front disks are more efficient on a spinning disk than a stationary one(why many 4wheel disk vehicles have a drum hand brake built into the rear disk) So if crossaxled(diagonally opposite front and rear spinning) try in low second progressively applying foot brake while keeping the wheels spinning(what traction control does but only the spinning tires) this will usually get ya out of a crossaxle as torque is sent across the diffs to the other tire and helps to lock up the lsd alltho rear drums do next to nothing when wet and full of mud.
One small warning low gear full power and full steering lock on the brakes gives CV joints arsholes avoid full lock if doing this!

Pritty common that they get the wrOng oil in them and fuck themselves, there shit, wear out to quickly, get some new clutches put in it or just go arb locker

I was under the impression they are a viscous LSD?

Originally Posted by Spanners

I was under the impression they are a viscous LSD?

Na not in the hilux/surfs,think some of the Nissans are.