Locker?

[provin1327]

Whats a locker?

[Danabee]

A place to keep your books.

[provin1327]

not that you fat terd lol, like a wheel locker or somthing, ive heard it before like "His front wheel locked but his back didn't"

[sarah]

Take it easy, no name calling!! We ban people all the time here.

Provin, that's such a basic question. Have you tried searching the web?

[blkTJ]

a wheel lock is a special "keyed" nut that isn't easily removable with a regular wrench. :cactus:

[NAILER341]

borrowed from FSB:

All About Lockers
I wrote this because I see a lot of info posted about lockers. Sometimes it's not right, sometimes it's incomplete, and sometimes it's very biased. I tried to put together a list of commonly available lockers and how they work. I know I missed some stuff and probably got something wrong. It would be GREAT if this could be made a sticky. I know this stuff has all been covered before, but it always gets buried, and it's the second most popular question behind "What gears should I use?" Additions/Corrections are welcomed. So here goes:

Lockers as I know them:

There are several types of lockers and limited slips out there. In my mind, there are three types of hard lockers, and several limited slips. First, I'll differentiate between lockers and LSDs.

An OPEN differential is one where ALL of the torque is sent to the wheel with the LEAST amount of traction. This is why one wheel will spin while the other doesn't.

A LIMITED SLIP differential allows SOME of the torque to be sent to the wheel with the MOST amount of traction. Better than open, but it WILL still slip when the traction requirement goes beyond the capability of the LSD to hold.

A LOCKER locks the axles together, sending equal power to both wheels, ensuring that the wheel with the most traction turns. A true locker allows some limited differentiation between the wheels. A wheel can spin faster than the ring gear, but not slower. (Parts of this definition were contributed by Weldmn)

Now, lets take a look at the different types of limited slips there are:

Trac-Loc - This is a very popular OEM type Limited slip that uses clutch packs behind the side gears to lock the axle together while allowing the wheels to spin at different speeds. Trac-Loc clutch packs look very much like automatic transmission clutch packs, but smaller. Ford uses Trac-Loc as the OEM limited slip if you purchased your vehicle with a limited slip.

Auburn Limited Slip - I don't know a lot about Auburn limted slips, but I believe they use a set of clutches and springs to provide the tension on the side gears.

Posi-Traction - I have no idea of the internals of a Posi unit, since I've never worked on one, but it's a limited slip like the others.

(Contributed by BlueBronco)
PowerLok is another clutch type limited slip by Dana that is pretty good but pricey for what it is.

(Contributed by Lonestar_Bronco)
Detroit Truetrac - a geared LSD with no clutches

Next up, lockers. Lockers fall into two distinct categories, with each category having it's own sub-categories. First we'll look at Automatic Lockers. There are two types of automatic lockers: Full Carrier Lockers and Lunchbox Lockers (those that are installed in the stock differential carrier).

Lunchbox Lockers:

PowerTrax Lock-Right - This is a very popular locker that is most commonly used in front axle applications. It is intended for light to medium duty wheeling, and will most likely fail when used in the rear of a heavy vehicle with large tires or a lot of horsepower.

PowerTrax No-Slip Traction System - PowerTrax does not call this a full locker, but it is. Basically, it is a modified Lock-Right with something they call a Synchronizing ring that eliminates the harsh engagement commonly found in the Lock-Right. I had one of these in a Full Size Jeep Cherokee, and it worked very well. I installed one in the rear Dana 44 in a Jeep and it broke as the guy pulled out of my parking lot. The syncronizer ring had a flaw and broke in half.

Detroit EZ-Locker - The EZ-Locker is basically the same as the Lock-Right. I have had both lockers, and visually there is very little difference between them. In use, the EZ-Locker seems to be smoother than the Lock-Right.

(Contributed by BlueBronco)

There are 2 other lunch box lockers . . . the Aussie and the QuickLok.

These all basically work the same way. A set of tooothed clutches replaces the spider gears and provides full and positive engagement of both axleshafts.

Full Carrier Automatic Lockers:

Detroit. This locker replaces the entire carrier assembly with a much stronger unit. The Detroit is the Gold Standard in lockers, and is suprememly strong. It was originally designed for military use. In fact, there is one exception to the carrier being replaced: 14-Bolt GM axles. The 14-Bolt carrier was designed to take the Detroit internals. That's why you pay so much less for a Detroit for a 14-Bolt. You don't need the carrier. Detroit lockers are ALWAYS there, and have quircky on-road driving charateristics. Off-road, Detroits are awsome.

GM offers the Gov-Loc, which is a GM OEM full carrier locker available in their Corporate axles. This unit normally operates as an LSD, but a counter-weighted locking mechanism locks the side gears together when the wheels have a speed differential of something like 100 - 200 RPM. It makes a very interesting "BANG" when it engages, and if you ever saw one you would be afraid to have it engage. They seem to work well, though, and GM has offered it for decades.

Selectable Lockers allow the axles to operate as open differentials until the vehicle operator engages the locker. There are at least 3 types of selectable lockers available: Air Operated lockers, Cable Operated lockers, and Eletrically operated Lockers.

Air Lockers:

The biggest player is ARB, and they are the Gold Standard of selectable lockers. ARB lockers require additional air system plumbing and compressors to operate, and they cannot be installed in a driveway by shade-tree mechanics. ARB installation is very complex, and unless you've done it before, it is a job best left to a shop.

The Jeep Rubicon uses a strange air locker from some company from Japan. It uses two little electric solenoid/compressor assemblies mounted to the frame rail. I have not seen these lockers sold independently.

Cable-Select Lockers:

The OX Locker is the first commercially marketed cable select locker, and has had mixed reviews. The biggest complaint is with the cables binding up and being unable to engage/disengage the locker.

Electric Lockers:

(This whole section contributed by BlueBronco)

Eaton makes the E-Locker and Auburn makes the Elected, and Detroit makes the Electrac. These electric selectables all work differently. The Electrac is like a True Trac limited slip when off and a detroit when on. The Eaton is like an open diff when off and is spooled when on. The Elected is like a ls when off and a locker (I think) when on. The Auburn is very complicated design wise. The Eaton doesn't have any external solenoids on the cover to whack but Detroit has resolved this on there newer designs as well.

Corrected by Weldmn
Toyota has had an electric locker available for it's axles for many years. You can buy this locker from TRD.


And then there are Spools.

A spool is a device that physically attaches the axleshafts to each other, permanently. There is no differentiation. There are a lot of different opinions on spools, but I will leave that debate to others.

There are three types of spools: Full spools, mini-spools, and Lincoln Lockers.

Full Spools replace the carrier and are very strong.

Mini-spools are like lunchbox lockers, in that they replace the spider gears, but use the stock carrier.

Lincoln Lockers - so-named because Lincoln is a famous brand of welder. A Lincoln Locker is nothing more than an open differential with the spider gears welded together. This is by far the cheapest method for locking a differential.

I will say this about spools:

You will wear your tires very quickly if you drive a spooled vehicle on the street for any period of time. You will chirp your tires whenever you make a turn, and it will drive very differently than a vehicle with a locker. That said, many people have spooled their rear axles and are happy with the results.

Some will say they have even spooled their front axles. They even sometimes claim that it behaves as if it wasn't there.

I have this to say about that:

DO NOT SPOOL THE FRONT AXLE. You will be unable to steer. Yes, you can take it out of 4WD to steer. You will get tired of this very quickly. You will be MUCH happier with a lunchbox locker in the front. There, I said it. I know this is a controversial subject, but I feel very strongly that front axles should not be spooled.

[provin1327]

ok thanks

[Jerry Bransford]

Here's something I wrote a few years ago that takes a little different angle from the really good info provided by Erik above. Sorry mine is pretty long-winded.

Here's something I wrote 4-5 years ago that was recently revived on another forum... I thought it might be useful here too.

Q: Why do we need lockers, I thought I had four wheel drive??

A: We need lockers for tough terrain because the differentials installed into most of our front and rear axles have a characteristic that can turn our 4x4 Jeeps into 4x2 Jeeps in tough traction situations.

A factory differential (sometimes called an "open differential") has a characteristic in that when one wheel loses traction, that wheel will start spinning ineffectively. You've seen that happen before, I'm sure. The bigger problem is that one spinning wheel on an axle causes both wheels to seem like they have very little traction... so even though the wheel on the other non-spinning side may have excellent traction, that non-spinning wheel won't receive enough power to keep you moving. Why? Because the differential screws up and only "sends power" to the wheel that is spinning. That is not technically totally accurate but it illustrates the problem very nicely, with a more technically accurate explanation as follows.

So the engine, via the drive shaft and differential, is seeing very little resistance from the axle with the spinning tire. So what? If the engine sees little resistance, it develops little torque. Low resistance to the engine, low developed torque. Lots of resistance to the engine causes it to develop lots of torque. Connect a dynamometer to an engine without a load on it and it'll show very little developed torque. Now put a brake of some kind against the engine output shaft (to add resistance) and the amount of torque developed by the engine will suddenly and dramatically rise. No resistance, very little developed torque... high resistance, a high amount of developed torque.

When a wheel starts spinning, the reduced resistance the engine sees from the axle causes the engine to dramatically reduce the torque it sends to the axle. Here's what else is going on that is a key to understanding this whole thing... a stock factory differential ALWAYS ALWAYS ALWAYS splits the torque it receives from the engine 50:50 to each wheel. Exactly 50-50, every time. So when one wheel is spinning and the engine torque decreases dramatically because of that, the OTHER wheel that still has good traction is seeing 50% of the greatly reduced torque. In fact, the torque sent to the axle is reduced so greatly that when the differential divides it 50-50, there is insufficient torque for the wheel with good traction to keep you moving. This means you're stuck!

So when you're driving on a dry paved road, both tires are receiving equal amounts of power and the high traction they're seeing from the dry road helps the engine to develop maximum torque. Both tires are pushing equally with lots of available torque. Now jack up a wheel (or lift it with a rock on a trail you just drove over) and you're not going to move even though the other tire is still on the ground. The tire in the air is spinning like crazy, causing the torque that axle receives from the engine to go right into the toilet.

So, when one tire on the axle is spinning, you don't have enough power for the other tire to keep you moving. For obvious reasons, all this is a huge problem for a 2wd vehicle (just one axle to drive you). It works exactly the same for a 4x4 but you have one more axle to assist in keeping you moving. But if one tire per axle has poor traction, you are stuck... since one spinning tire per axle is enough to reduce all developed torque from the engine down below the point the Jeep needs to move forward.

OK, we know what the problem is now, what's the fix? One, you could STEP ON THE BRAKES a little... which would stop the tire(s) from spinning so more torque would be developed, which should be enough for the OTHER tire that still has good traction to get you moving again. Yep, stepping on the brakes (to a point best learned by practice) works rather well in these situations. Just about all drivers used to know that technique when few roads were paved... but it's just about a lost art now.

So what does a locker do? It mechanically LOCKS the left and right wheel together to overcome the above problems. It won't allow one wheel to start spinning while the other sits doing nothing. The left and right wheels are mechanically locked together.

Automatic lockers keep the left and right sides locked together except when you turn left or right, where it will automatically unlock the outside wheel during the turn until after the turn is completed at which time it locks up again. When the locker unlocks for a turn, the outside wheel is allowed to rotate faster than the inside wheel so it doesn't hop and skip during the turn. The inside wheel is driving during a turn with an automatic locker-equipped vehicle. The locker automatically locks again once both wheels are turning at the same RPMs again.

The problem with an automatic locker is that most are not very street friendly. Because they keep the left and right wheels locked together except when forced to unlock for a turn, they can cause unusual handling characteristics like rear-end waggle, tire chirping, disconcerting loud bangs and snaps from the locker, and even sideways sliding down slippery off-camber slopes where they earned the nickname "low-side finder"... which can sometimes produce a high 'pucker-factor' at times. For offroading however, locker's negatives are far outweighed by their benefits in challenging conditions.

A manual locker is "open" (unlocked) until you actuate it. The ARB Air Locker and the cable-actuated Ox-Locker are examples of manual lockers. These are good because they remain unlocked until you choose to lock them. This eliminates the handling problems automatic lockers have on the streets.

By the way, a locker is installed inside the differential and it replaces the "spider" gears that make a differential work they way it does.

So some Jeepers add lockers in the rear, others add them to the front. I happen to think locking the rear axle first does the most good, but I have installed automatic lockers into both of my axles... which works pretty darned well. But if your rear axle is the notoriously weak Dana 35c that comes stock on all Wranglers except the Rubicon and Unlimited, avoid installing a locker in the rear axle and install it in the front axle instead. Since the front axle rarely receives more than 50% of the torque that the rear axle does, it can usually handle a locker without problem with reasonably sized tires like up to 35". But if your rear axle is the optional and far stronger Dana 44, by all means install a locker into it if your trails are tough enough to make a locker desirable.

So what's a limited slip differential? First, it is not the same as a locker. It is more or less an automatic brake for the spinning tire... it performs kind of like when you use the step-on-the-brakes technique so the spinning side gets coupled to the non-spinning side for more resistance so more engine torque can be generated so the non-spinning tire receives more torque from the engine to help get you moving again. It operates as a brake somewhat by coupling the added resistance of the side with more traction/resistance to the side that has less traction/resistance. A LSD depends on some tire spin to get it working so it's not as efficient for challenging terrain as a locker is. But then generally speaking, a LSD is far more "driver friendly" on the streets, which is why we all don't just have lockers in our Jeeps.

Hope this helps a little.

[killwhytey07]

you've got a lot learn my friend, I suggest if your gonna by a jeep, stop by an autozone, or other parts store and pick up a chiltons, or haynes guide for the vehicle. It'll give you the low down on the entire jeep, and how to fix/mantain everything on it.

Also, check out the web or the library for books on off-road rigs, theres a lot to know, depending on how far you wanna take it.

again, good luck!

[RAT]

Well here's one thing fer sure. Stick around here and if you don't know it now, ask enough questions and you will. I learn something new every time I log on.

"You're never too poor to pay attention"

Rat

[peteyg]

borrowed from FSB:

Hey! I wrote that! I'm famous!:thumbs_up

[NAILER341]

Hey! I wrote that! I'm famous!:thumbs_up

boy, i am sure glad i didnt try to claim it as my own

[blackZZR]

Jerry I have always liked that bit you wrote about lockers, open diffs and limited slips. It does clear up a lot of stuff and explain the difference of a perfect world vs the real world. Great piece.
We are now living in a world where traction control is coming standard on vehicles and computer controlled axles actuated by the antilock brake systems are becoming more normal in the 4x4 world.
Systems like the last generation of Toyotas Atrac system are showing what can be done on lower end vehicles. We are no longer looking at these systems on higher end vehicles like Grand Cherokees and Range Rovers.
Guys running these systems are rethinking along the lines of traditional traction control. I have to admit, the difference between 2 detriots in the wrangler, and the Atrac in the FJC is not much and they keep improving computer programs every day.
I wish jeep would release a system on the Wrangler simular to one of those, it is the only thing that would get me out of my 04.