Why do I need a locker? I thought I had 4X4! - Page 8 - JeepForum.com

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post #106 of 123 Old 11-09-2012, 07:58 PM
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Great posting!

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post #107 of 123 Old 03-30-2013, 11:56 PM
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I've been lurking on quite a few forums for a while but cant help but ask for help from someone to explain something I can't get my head around in regards to auto lockers.

Jerry mentions that auto lockers operate on a ratcheting type system...

So what goes on when you reverse


If it's a one way ratchet system, does it not mean the ratchet will ensure no motion going through to the wheels when you are running backwards.

It's probably an easy answer, but it would be nice to know from a technical point of view how it works in reverse, and if the auto locking design is just as effective and faithful in reverse.

A manual locker is just as good for forward and reverse. What about the auto lockers?

This is a very educational and interesting thread, explained simply. That's why I decided to whack my technical question in this particular thread on this forum, so it's included for ever
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post #108 of 123 Old 04-01-2013, 02:09 PM
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The Aussie auto-locker isn't really a ratchet system per se, but utilizes interlocking teeth that have double bevels. When the locker locks up it is a solid connection, no ratchet at work. The two halves of teeth can be easily moved apart with light spring pressure when torque is reduced or removed. There is sometimes a ratcheting sound emitted when the differential is "open" when the auto-locker has disengaged when the vehicle is doing a turn on dry pavement. The auto-locker performs the same in forward or reverse.

The Aussie is a nice piece of gear, got my Jeep out of some super sticky muck holes.

Check out their site for some FAQ's.
http://www.aussielocker.com/how-it-works#answer3
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post #109 of 123 Old 04-22-2013, 05:36 AM
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Ahhh. I see.

Thanks for explaining Paul.
I'm late replying because I never received an email alerting me to your post after I subscribed to this thread

I'll check out the Aussie lockers.

I've gotta choose one soon.
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post #110 of 123 Old 12-01-2013, 09:10 AM
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Very interesting post
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post #111 of 123 Old 05-27-2015, 12:26 PM
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I have Spartan auto lockers in mine. I will tell you that if I had it to do again I would go with a electric locker in the front. It makes a lot of popping sounds when you turn and sometimes it scares the crap out of me. I ended up pulling mine out of the front and putting a open carrier back in. It isn't that bad at all in the rear differential.
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post #112 of 123 Old 12-23-2015, 03:27 PM
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Originally Posted by OregonVette View Post
Thank you for the great post Jerry!

Say, in regards to many of the newer JK owners, the most modern JK has an outstanding BLD, ESP, Dana 44 rear and some (most Saharas) come with TracLok. Your OP was written before the new JK came out. If I could just add a few things so newer jeepers just don't run out & buy a new locker which may be unneeded.

After just completing the Naches Trail run, you'd be surprised at how capable, flexy, and downright awesome the most modern JK is. Granted, I'm old enough to remember having to go outside and "flip" the hubs to get them locked, i wholeheartedly appreciate fully locked rigs but...

Before this last 5 day adventure tour, I was certain I was going to add ARB air lockers to the Four door JK Jeep. Nope, again I was thoroughly impressed at how well these three components work together (all JKs have a D44 rear):
1. Traclok
2. ESP
3. BLD

Plus, adding front sway bar disconnects will keep the front two tires on the ground, where they belong even in the most funky off-camber pucker inducing event.

I will not be adding air lockers to the JK after all.
At the end of every day, all the old-timers in their flat fenders and even many of the youngster in their TJs would come over and look at the JKs and say how impressed they were & how they were certain the new JK could never keep up etc... Once they get towed out by a "mini-van" their tune changes a bit!
Yes, thanks Jerry for the info! Very informative.

As OregonVette mentions... for those with late model JKs, how much do the features on the newer models ameliorate the need for lockers? For example, my JKU Sahara sticker indicates the following:

"Traction Control" listed under Standard Equipment
"Electronic Stability Control" listed under Standard Equipment
"Anti-Spin Differential Rear Axle" listed under Optional Equipment

Do these features, when combined with lift and off-road capable tires, significantly reduce the need for lockers for all but the most difficult situations?

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post #113 of 123 Old 12-27-2015, 03:55 PM
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Quote:
Originally Posted by DHart View Post
Yes, thanks Jerry for the info! Very informative.

As OregonVette mentions... for those with late model JKs, how much do the features on the newer models ameliorate the need for lockers? For example, my JKU Sahara sticker indicates the following:

"Traction Control" listed under Standard Equipment
"Electronic Stability Control" listed under Standard Equipment
"Anti-Spin Differential Rear Axle" listed under Optional Equipment

Do these features, when combined with lift and off-road capable tires, significantly reduce the need for lockers for all but the most difficult situations?
Onroad those things can be valuable, but offroad they are of little value IMO. They in no way get you even remotely close to being locked.

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post #114 of 123 Old 12-27-2015, 06:38 PM
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Onroad those things can be valuable, but offroad they are of little value IMO. They in no way get you even remotely close to being locked.
Thanks. I now have a much better understanding of the value in the Rubicon's lower gearing, Dana 44 front axle, and the lockers. Rather than pour several thousands of dollars into our Sahara for aftermarket gearing, adding lockers, rear tire carrier, D44 front axle etc. I think it makes a lot more sense to trade the Sahara for a Rubicon, as the upgrades I have been wanting to do would already be done at the factory and will retain much of that value at resale/trade down the road, whereas the aftermarket upgrades done to the Sahara would not likely return much, if any, more than a stock Sahara at resale/trade in time. And.. those upgrades would be financed into the vehicle loan on the Jeep, rather than be big dollar outlay from my pocket right now.

So, for me, I think doing a trade of our 2013 Sahara for a 2016 Rubicon makes the most sense financially, in the long run.

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post #115 of 123 Old 04-26-2016, 09:15 PM
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Originally Posted by Jerry Bransford
Here's something I wrote 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 our front and rear axles have a characteristic that can turn our 4x4 Jeeps into 4x2 Jeeps in low 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 lose power to the point you can't move your Jeep... 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 the engine develops and 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. Stepping on the brakes forces the engine to work harder so it develops more torque which is sent to the wheels... so that gets more torque sent to the wheel (both actually) that still has traction so you may be able to get unstuck. Yes, 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 when installed in the rear axle. 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. But in many Jeeps like the TJ, an automatic locker is fine when installed in the front axle. Since the front axle doesn't receive torque in 2wd, a front automatic locker unlocks easily enough for turns that you may not even notice its presence. Only in 4x4 is the front axle receiving torque which makes it harder for the locker to unlock for turns. About the only conditions where an automatic front locker would not be good in the type of 4x4 system a Wrangler TJ has would be on icy or snow-covered roads where you need 4x4. In 4x4, a front automatic locker would cause understeer (make the Jeep want to drive straight in a turn) which would not be good if the road was slick from snow or ice. 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 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 into it and install the locker into 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. 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.
this is so helpful
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post #116 of 123 Old 06-28-2016, 08:54 AM Thread Starter
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Originally Posted by TJoker View Post
I have Spartan auto lockers in mine. I will tell you that if I had it to do again I would go with a electric locker in the front. It makes a lot of popping sounds when you turn and sometimes it scares the crap out of me. I ended up pulling mine out of the front and putting a open carrier back in. It isn't that bad at all in the rear differential.
Don't let your bad experience with Spartan lockers scare you away from all automatic lockers up front. Not to mention I have read of similar bad experiences with the Spartan locker.

I ran the No-Slip automatic lunchbox locker up front for years and you really couldn't even tell it was there in 2wd. You could only tell it was there once you shifted into 4x4.

When you have a choice, buy American made.

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post #117 of 123 Old 02-01-2017, 10:18 AM
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Great info here, thanks all...
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post #118 of 123 Old 02-05-2017, 03:49 PM
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Nice post - very informative
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post #119 of 123 Old 03-23-2017, 05:49 PM
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My brand new Powertrax No Slip has a cracked gear, not even 100 miles on it and less than 5 minutes in 4 low, on dirt, and one trip up a RTI ramp.

The shop installing my new gears today called me and sent over a picture. I called Powertrax and they will only inspect it and then make a determination if it's covered in 6-8 days. Needless to say, while I love the idea of how it works, I'm not putting another one in, going with a Lock Right for many reasons, the biggest being it was available today and it's $150 less. I'll put up with some banging and clunking at this point. The Jeep is at the shop for gears and I really don't want to pull it apart again if I can help it. Fortunately, I can still return the No Slip thru Amazon (less than 30 days old) so I'm not out anything except return shipping.

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post #120 of 123 Old 03-26-2017, 07:49 PM Thread Starter
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You simply got a defective No-Slip which is highly unusual, I ran one hard for years without problem. That'd be a step backwards going with the cheaper Lockrite. Same manufacturer for both lockers you know right?

And keep in mind that even the very best made products aren't always 100% problem free. Odds are you wouldn't have any issues with the replacement. Just make sure it is properly installed. Who knows, maybe the first one was not.

When you have a choice, buy American made.

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