rear end explanation PLEASE

traction lock and limitied slip are the same thing, v6s one wheel is being driven all the time and one is spinning freely, it is the same for V8s but the v8s have traction lock/limited slip, there are clutch packs inside the carrier that sense when the right wheel spins faster than the left so it kicks in and makes the left spin just as fast, when you are cruising around town driving normal only one wheel is driving but when u gun it or do a burnout traction lock kicks in because it feels the right wheel slip and then the left keeps up with it, if you car is pulling one leggers you need new clutch packs, a true posi rear end is both tires always being driven and not just spinning freely.

beat me to it...

Open diff - TQ is transfered to the wheel with the LEAST traction. There is no locking action whatsoever. You see this when you get all over the gas and only one wheel spins. It lost traction and so all the power is being diverted to that side. This is what is in the V6 Mustangs.

Limited Slip diff - These have a clutch type arrangment (ours use a clutch, others may be a cone type posi) inside so that power is evenly distributed to both wheels until the differential bias is achieved. At that point, the diff will transfer any extra TQ to the wheel with less traction. This usually creates a lot of heat in the diff and causes the clutch to slip. Therefore, in a very short time, the clutch will act as an open diff until it reengages and cools down. This is an example of preload vs. bias ratio. Our limited slips have decent preload but no bias ratio. Think of it like a guy who can bench press 500 lbs, but only once. He has good strength but no endurance. These are what we have in the V8 Mustangs, known as a traclock.

Locked diff - Locked diffs transfer power to both wheels equally regardless of how much power is applied. They will continue to do this until sideloads are imposed on the diff, indicating a turn. Also known as a locker, these act as a spool while driving straight but disengage and act like an open diff while turning. Most lock much easier than unlock and so are typically seen in cars whose main goal is straightline traction (drag cars).

An example of this would be the Detroit locker, probably the most famous locker out there (and rightfully so). It works very well in the straightline, but tends to be pretty noisy and ratchety in turns as it attempts to disengage.

Another example would be the air locker, which uses a small air compressor to manually lock the diff solid. It will remain in this configuration, regardless of straightline driving or cornering until the diff is manually unlocked, usually done by flipping a switch. In that configuration, it is basically a spool.

Spooled diff - A spool locks the rear end solid. It transfers power to both wheels equally regardless of turning, straightline, TQ input, etc. It is bar none the best diff for the drag strip but a miserable experience on the street. With a spool, both tires will ALWAYS turn the same amount and in the same direction. The only exception to this is if you break an axle. And even then, that little stub of an axle in there will be turning with the wheel that's still being driven.

Another point to mention is that with lockers and spools, it's easier to break axles. Even with a stock mustang, a spool and slicks can kill an axle shaft if abused.

You also have an electronic locking differential where you can lock/unlock it with the flip of a switch. I am getting ready to get a new Eaton posi and Strange axles so I can pound on her all I want.

nmcgrawj said:

Can someone please explain the different rear ends and features (limited slip, tractoin lock, etc) that came in stangs. I know in mine when i got stuck that sometimes only one wheel would spin.....

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Someone dident watch Popular Hot Rodding Television this morn . They had a big segment on all the diffrent kinds.

nmcgrawj said:

How much is it to get the clutch packs rebuilt? If i pop the clutch both wheels spin ( i think every time) but sometimes when i do a burnout only one tire will leave a black mark and the other tire will lleave a much lighter mark.

Please shed some light...how much performance am i losing if the clutch packs are dead?

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Yea I'd like some information on rebuilding the clutch packs as well, I posted on another stangnet board and all I got was "wow you're stupid why don't you know that"......well maybe because I've never done it before.....but yea some help would be nice

It's not true about one wheel getting all of the power with an open diff. If the tires are not spinning, or slipping, each tire is getting roughly 50% of the power.

Now for the technical stuff. There are two things working in tires. Stiction and friction. Friction is the ammount of force that it takes to pull your tire over the road. Immagine a car stopping with all four wheels locked up, the friction force is what is slowing it down. Frictional force varies with tempature, contact patch area and tire pressure. Stiction is the initial force required to start the tire slipping. Stiction is always higher than the frictional force, that is why all new cars have anti-lock brakes, you stop faster if the tire stays in contact with the ground.

Now, when one tire starts slipping with an open differential, it's frictional force will almost always be less than the stiction force of the other tire, so the spinning wheel keeps spinning and the other wheel justs sits there.

A positraction type of differential uses the difference in speed between the two axles to push together the clutch packs. This force created by the clutch packs causes power to be transfered to the non spinning wheel, and the idea is that the wheels will start spinning at the same speed and they will not be slipping any more.

I hope that explains it for every one, come back next week for detroit lockers.

At this point I'm all about theory since I have not rebuilt an 8.8 yet. Sorry

IMO
My advice, having replaced gears in a couple of limited slip rear ends............don't do it. Pay someone to do it for you!

Your other option, find what you want in a junk yard car and replace the entire rear axle.

Rear ends can be nightmare.