Hey guys! ChrisFix here.
And today, I'm going to show you how to rebuild a limited slip differential...
...and install carbon fiber clutches.
So if one of the wheels starts to spin and slip,
these clutches are going to engage and grab on to each other
to send power to both wheels,
so you'll get more traction which will give you better acceleration,
and better handling.
Now, not only are we installing the clutches, but I'm also going to be installing
a brand new finned aluminum diff cover which is going to help with the cooling
because it's good to keep the brand new clutches cool to make them last longer.
Plus, this has a drain bolt and a fill bolt
so we don't have to remove the cover to change the fluid.
And down the road, if we want, we could add a temperature sensor
and an oil cooler to our diff.
Now how did I know the limited slip differential is worn out
and I needed to install new clutches?
Well, it all started at the track when I was drifting.
I was having an epic day, I was learning so much, and I was just killing it out there!
But every once in a while randomly, the rear end would feel completely different
and that was making it hard to be consistent.
Then, I was at the drag strip ready to race Adam LZ
doing my burnout to get those tires hot and sticky.
But if you notice, only one wheel was spinning.
I was doing the classic "one wheel peel."
It was so bad that everybody thought I broke my axle.
"Your axle's broken."
And that's when I knew my limited slip was completely worn out and needed a rebuild.
Now, rebuilding your limited slip differential isn't only for a track car,
it's good for any car where you might run into a situation where you loose traction.
Maybe you're using your daily driver on the road
and it's raining or snowing,
maybe you have a truck or an SUV, you're towing something or you're going off-roading,
or you live on a road where there's dirt, there's mud.
Any situation where your tires might slip,
a fresh limited slip differential is going to give you more traction.
Now, how do you know if your car has a limited slip differential?
Well, one way to tell is to go under the car,
find the rear differential, and look for a tag like that.
And if you have a tag like this, it gives you a lot of information.
So we have 3 27 gears in here,
and this is an 8.8 rear end.
In between the 3 and the 27, you can see there's an L.
That means it's limited slip.
And for another example, if we take a look under my truck,
we have a similar rear end, and you can see our tag right there.
And this tag shows 4 10 gears and an 8.8 rear end,
but there's no L here, so it's an open differential.
Now not every differential still has the tag on it,
so how do you figure it out if you don't have the tag?
Just go to your door jamb there is a sticker right here with your VIN number.
Take that VIN number,
and then type it into a VIN decoder.
Just do an internet search with your car's make and the word, "VIN Decoder,"
enter your VIN, and it'll give you a bunch of information
including the options the car has such as a limited slip differential.
So, those are some ways you can see if you have a limited slip diff.
And rebuilding your LSD is actually really simple once you know what you need to do.
So I'm going to give you a step-by-step guide, I'm going to show you
everything you need to know so you can easily do this at home
in your driveway with common hand tools.
I'll also be sure to link all the products and tools that I'm using
in the description so you can easily find them.
So, let's begin!
And the first thing we want to do is soak our new clutches in friction modifier.
So grab all the clutches and put them in a container and spread them out,
and then pour in your friction modifier.
We want these clutches to soak for at least 15 minutes
so when they get installed, it'll engage smoothly
and it won't make any noise.
And once these are all covered, now let's start working on the car.
So with the rear of the car safely jacked up and supported by jack stands,
the first thing that we need to do is remove our brake calipers
because we want to slide this axle outwards.
In this case, I have a dual caliper setup, so I have two brake calipers, this is custom.
Most cars will have a single caliper or a brake drum that needs to get removed.
And in order to do that, it's really simple, there's a bolt holding it in up here,
and a bolt holding it in right down here.
So let's start at the top bolt.
Crack this loose and unscrew it all the way.
Good.
And unscrew the bottom bolt as well, but here we have an E-brake cable in the way.
So I'm going to use a box end of a wrench to loosen this, which will fit right in here.
And once that bolt is loose,
slide the caliper up and remove the bolt the rest of the way.
Now with the caliper loose, we can slide it off.
But before we do that, grab a bungee or something similar
and hook it onto the suspension.
That way when we remove the caliper, we can hold it up with a bungee
so it doesn't hang from the brake line, which could damage it.
Now we can remove that second brake caliper.
That's the top bolt.
Then unscrew the bottom.
Good.
Slide the caliper off, and we can rest it right on the lower trailing arm.
And finally, let's remove the rotor.
So with the brake calipers removed, the only thing that's holding in this axle
is the C-clip in the differential.
So let's slide under the car and we're going to remove this differential cover right here.
It's held in by 10 bolts around the perimeter.
But before we remove those 10 bolts, it's important that we slide an oil catch can
underneath the differential so that when we open this up, the differential fluid comes out
and doesn't make a mess.
Now it's also a good idea to come to the front of the differential and make sure you
can remove the fill bolt.
Use the box end of your wrench and make sure it comes all the way out.
You don't want to drain the diff and not be able to fill it to the correct level.
So with this removed, now we can remove the diff cover and drain the fluid.
You want to start by removing the bottom bolts first and work your way up
so if the gear oil starts leaking out, it's a controlled leak from the bottom,
and it won't make a mess.
And for that last bolt up top, we want to unscrew this about halfway so it's loose,
but at the same time, the cover won't just fall off.
Now we can pop open that diff cover and drain all that gear oil out.
And if your cover doesn't come off easily,
you might need to use a screwdriver to get it in there and pry it open.
So after all our diff fluid is drained out,
now we can get to that top bolt and remove it completely,
and get this diff cover out of our way.
Now luckily, most of the gasket material came off with the diff cover.
But there's still some leftover gasket on there that needs to get cleaned off.
So cover the gears with a bag so they don't get dirty,
and I like using a plastic scraper to remove the old gasket because plastic can't gouge
the flat metal surface on the diff.
Now with the differential gasket surface smooth and clear of any old gasket,
we are ready to disassemble the rear end.
So to make this job really simple and really easy for you,
I'm going to be showing you how to do this without removing this carrier,
which is this whole assembly right here.
Instead, we're just going to be removing these spider gears and side gears
so that we can get to the clutches.
This is what a clutch looks like, this is a carbon fiber one.
The stock ones aren't carbon fiber.
But they do have these tabs here, and you can actually see the tabs there, and there.
So we need to get in there to pull those clutches out and install brand new ones.
In order to do that, we have to turn the differential until we find the lock bolt,
which is right there, which is holding this pin in.
This is an 8-millimeter bolt and a ratcheting wrench makes this so easy to do.
Also, if we don't put the car in 1st gear,
then you're just going to spin the differential.
So put the car in 1st gear, or if you have an automatic, put it in Park.
And now the transmission's going to hold this so that we can loosen this bolt.
Good.
Now, slide your hand behind the differential and push on the other side
to knock that pin out a little bit.
And now, we can slide the pin out all the way.
Beautiful.
Now, we want to put the car back in neutral and spin the axle
so we have access to our spider gears, C-clips, and spring.
Taking a closer look, you can see the end of the left axle
and the end of the right axle.
Next, we want to push the axle inwards,
and that gives us access to our C-clips right there.
Then we can use one of these stick magnets to get it in there
and remove that C-clip.
Perfect!
Since we're doing both axles,
you might as well get that other C-clip while you're in there.
Now we can pull the axle out about 6 inches.
That's plenty of room, and if you want, you can pull it all the way out.
And now's a really good time...
...to replace your bearing and your seal.
I already replaced these when I did the dual caliper setup.
It's really cheap, really easy to do, and it's great preventative maintenance.
But since I already did it, let's go back under the car,
and we can remove our S-spring, which is this right here.
Now, this spring is compressed right now, and under tremendous amount of pressure.
So you have to be really careful and make sure you have your eye protection on.
And to remove it, we're going to use a hammer.
So I like to use a piece of wood that fits right over the spring,
and then carefully tap that spring until it can't move any further, like that.
Then we can spin the carrier and get to the spring on the other side.
Next, clamp onto the spring and give it a wiggle and pull it out.
And you might need to use a screwdriver to help...
...pry it out.
And there you go, that is how you safely remove that S-spring.
You can see how our clamping pliers did not let go of it.
So that's a good trick to do when you're trying to get this out.
Now, before we remove any gears, with a differential, it's always good practice
to reinstall the gears exactly where they were.
So grab a paint marker and mark the gear and differential so we know where it goes.
And we can do the same for the side gear as well.
And for the bottom spider gear, I'm going to use red.
As well as for the other side gear.
Perfect, with all these gears marked so we know exactly where they go,
now we can remove this top and bottom spider gear.
To remove them, all you have to do
is spin the side gear with your finger,
and get ready to catch this as it comes out.
Just like that.
And these spider gears have a washer on the back.
You can see that washer there, make sure it comes off with the spider gear.
And in order to get that other spider gear, just spin the side gear again.
And then make sure you pull it out with that washer on there, perfect.
So, both of the spider gears are out.
Now we have to remove the two side gears.
Because we have a ring gear here, we can't get to this side here.
This won't come out all the way.
So we're going to remove this one first.
And to remove this, it's really easy, you just pull it right out.
Beautiful.
And once thing I noticed is this side gear doesn't have a washer on the back
and there should be one.
So just make sure you remove the washer from inside here.
Just like that.
Next, remove the driver's side side gear the same way.
And it should just slide out like that.
And this one came out with the washer.
So let's go and replace the clutches.
This is really easy to do, we're going to work on one side at a time,
and the order of the clutches and the plates on the side gear is very important.
You can see we have that thin washer on the outside,
so when we separate this, we want to keep this in order.
What I like to do is lay everything out in order, we have the washer,
clutch, steel plate, steel plate,
clutch, steel plate, clutch, steel plate.
Then we can grab our carbon fiber clutches which have been soaking in the friction modifier.
And a little trick that I use is put these in a sealed bag
because this friction modifier smells horrible!
So we can grab three of the six clutches because we're doing one side at a time.
And then we can grab a set of steel plates and a washer,
and lay out the washer, clutches, and steel plates in the same order as the stock setup.
So we have the old clutch pack and new clutch pack,
and I mean, look at the difference in the clutches.
These new carbon fiber clutches are going to make a huge difference.
Now I'm kind of curious how worn out this old clutch pack is,
especially compared to the new one.
So you can use a caliper to measure it.
So we'll start with the old clutches.
Grab a C-clamp and clamp them down, make sure it's nice and tight.
And if the old clutches are worn out, it'll be thinner than 0.635 in.
And look at that, in this case, 0.632 in.
These things are worn out.
Now, let's check out the brand new performance clutches.
Now, this should be right around 0.655 in. for a performance clutch pack.
And it's 0.656 in.
So our brand new clutch pack is thicker than our old worn out clutch pack.
So, out with the old, and in with the new.
And all we have to do is get the side gear,
make sure our thin washer is on the outside,
and then just wiggle it right into place.
Perfect, so our driver side clutch pack is done.
For the passenger side, it's the same exact process,
so get the new clutch pack on there, and we are ready to install these in the diff!
Back at the differential, installation is opposite of removal,
so grab your driver side side gear.
And you see these clutch ears here? We want those to be aligned.
So straighten them out,
and slide that side gear into place.
It goes in really easy, and you can see how the clutch ears need to get aligned
to fit properly.
Perfect.
Now let's do the same for the passenger side side gear.
Get the clutch ears straight
and slide it into place.
Now we can install our spider gears.
And the back of the spider gear
fits into these little cups here and here.
And what makes installing spider gears tricky is that
the washers on the back here come off very easily.
And they have to stay on
otherwise, they'll just fall in the diff.
So a little trick is to pop the washers off the back of the gears
and then add a little gear oil that you're going to be using to fill the diff later on.
Then press the washers back on,
and the oil's going to hold those washers on pretty tight.
Plus, it's always good to lubricate this anyway.
The next trick to installing spider gears is to install them at the same time.
We remember we have the green which goes to the top
and the red that goes to the bottom.
And these have to be on the exact opposite sides of each other,
so get your hand behind the carrier and push that spider gear in.
Then put the other gear right in the front on the exact opposite side.
Now, turn the gears so they move into the cups where they should sit.
Good.
Now, you want to make sure they're in correctly, so spin the carrier,
and then push the cross pin through the hole,
and make sure it goes all the way through both spider gears just like that.
Good.
Now that all the gears are in place,
this next part is probably the hardest part of this whole job.
And that's installing the S-spring.
Now, on my Mustang, we have to actually reuse the old S-spring
because the new one's too thick and won't fit.
But even the old one is too difficult to get in there.
It's hard to compress, so you can't just push it in.
So the trick to get the spring in...
...is to use a vise and compress it.
And if you don't have a vise, you'd always use a C-clamp like this.
It won't be as easy, but you'll be able to compress it.
But luckily, I have a vise, so get this spring in the vise
and clamp down as far as you can go so that spring is completely compressed.
Then, grab a needle-nosed locking pliers
and clamp down on the spring to keep the spring compressed.
Then open up the vise,
and the locking pliers is going to keep this spring compressed
so it's small enough to fit in the differential.
So slide the spring into place,
And even though it's compressed, you still need to get it started by tapping it in there.
And once it's in a little bit, unclamp the spring,
and tap it the rest of the way in so it's as centered as you can get it
in between the gears.
To verify it's centered, slide the cross pin into the hole,
And you can see it gets stuck, so tap the spring a little bit more...
Perfect.
And now, the pin can go all the way through, so the spring is centered
and correctly installed.
Next, we have to push the left
and right axles back in.
And then grab a C-clip and slide it back into the slot in the axle.
Finally, pull the axle outwards
to lock it into place.
Do the same thing for the other axle.
Slide the C-clip into the axle,
and then pull on the axle to lock it in place.
Now, turn the carrier so we can install the differential cross pin,
which you can push into place until it's flush with the carrier.
Now, we want to install a brand new cross pin bolt.
Never reinstall the old one because the new one has thread locker on it,
which prevents it from backing out.
If this bolt does come loose, it will destroy the differential,
and you definitely don't want that.
So torque this down to 25 ft-lbs, which is about as tight as you can get it
with this small wrench.
Good.
Alright, we are almost done.
I cannot wait to do a burnout and test out those clutches.
So our differential is fully assembled, the clutches are in.
Now, it's time to install our brand new diff cover!
So with the gasket surface completely clean,
we can either use a paper gasket, or use an RTV gasket maker.
I suggest a paper gasket, it's a lot easier and they're inexpensive.
But if you can't find a gasket, or if you don't have one, you can use this RTV,
and I'll link a video in the description on how to use this.
So when using the paper gasket, the hardest part is aligning the bolt holes
and keeping that gasket there, because when you let go, it's just going to keep falling down.
So a little trick is remove the gasket
and apply a little bit of gasket sealer.
This sealer is a tacky liquid that helps the gasket adhere to the surface,
and you just need to apply a thin layer, like that.
Then align the gasket and press down so it sticks to the surface.
Now grab your diff cover, and it's very easy to align the cover
and get that top bolt in because the gasket isn't going to move out of alignment.
Also, since the new diff cover is thicker,
I'm using these longer bolts,
so keep that in mind if you switch to an aftermarket cover.
So now, let's hand tighten all 10 of these bolts which holds the cover in place,
and then, grab a torque wrench, and these bolts should be tightened down to 25 ft-lbs.
A little trick I use to keep track of the bolts I torque down
is to mark them with a paint marker once it's torqued.
This helps a lot, because you're going to be torquing these bolts down
in a crisscross pattern.
That way, the diff cover compresses the gasket evenly for a leak-free seal.
And with the new diff cover torqued down, it's good to go!
Now, let's add some differential fluid.
I'm using a full synthetic 75W-140 gear oil
which is made for limited slip differentials.
But it's also recommended that you still run 4 oz. of friction modifier
so the clutches can engage and disengage properly.
I also highly suggest getting one of these pumps
which screws right to the top of the bottle.
That way, you can remove the fill bolt on the diff cover,
slide the pump hose into the diff,
and very easily pump the gear oil
into the differential without making a mess.
Keep in mind that the car should be relatively level when filling up the diff
so you don't overfill it or underfill it.
And since this diff holds about 2 quarts of oil,
you're going to have to use two bottles of gear oil.
So once one bottle is empty, switch over to the new bottle.
And you can always check the back of your owner's manual
to see how much oil your diff holds.
But to know it's full, just keep an eye on the fill hole at the front of the differential.
Once oil starts seeping out of there,
stop pumping, because your diff is full.
And we're so close to being done,
so let's screw this fill plug in so we can stop the leak.
And let's also screw the fill plug in on the top of the new diff cover so it's snug.
Good.
So with that, our rear end is completely done,
and we have one thing left to do, and that is the brakes!
So put the brake rotor back on,
then grab a caliper and slide it over the rotor.
Hand tighten the top bolt, and then hand tighten the bottom bolt.
And I need to get the other brake caliper on as well,
and also hand tighten these bolts as well.
And finally, we can torque down all the caliper bolts to 76 ft-lbs of torque.
Then, install the wheel and torque down the bolts in a star pattern.
Alright, now we're going to go for a ride,
and we don't just want to go out and do some burnouts and rip on the car.
For the first 100 miles or so, you want to drive around regularly,
and let those clutches break in.
That way, they can last a good long time.
And finally after 100 miles, we're heading onto the track.
Moment of truth, let's see if we can lock up the rear end and spin both tires.
Awesome! This feels so much better,
and I can see that both tires are spinning and making smoke
which is what you want to see.
No more one wheel peel!
Now, that's how you rebuild a limited slip differential
and install performance carbon fiber clutches.
Hopefully, the video was helpful. If it was, remember to give it a thumbs up.
And if you're not subscribed, consider subscribing.
As always, all the tools and products I used
are linked in the description so you can easily find them.