I know, another Locker vs anti spin Diff question

[Stormin’ Moorman]

I may be wrong here, but fully locked sends 25% power to each wheel all the time. This is best case scenario when traction is very poor. Otherwise the Rubi has an open diff, which is the best for on pavement. With the Sahara, which has rear LSD, you're sending 50% of the power to front and 50% to the rear. So you could have one front wheel spinning and the other not moving. The rear LSD should make adjustments when one the rear wheels loses traction. So worst case is you have 3 wheels turning. I have a Rubi but the 4x4 system on the Sahara is superior for most people, most of the time. Its just easier.

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[Sean L]

I may be wrong here, but fully locked sends 25% power to each wheel all the time. This is best case scenario when traction is very poor. Otherwise the Rubi has an open diff, which is the best for on pavement. With the Sahara, which has rear LSD, you're sending 50% of the power to front and 50% to the rear. So you could have one front wheel spinning and the other not moving. The rear LSD should make adjustments when one the rear wheels loses traction. So worst case is you have 3 wheels turning. I have a Rubi but the 4x4 system on the Sahara is superior for most people, most of the time. Its just easier.

I think the only way you could have one front wheel spinning with the other not moving at all is if you also lose traction with both rear wheels with LSD. There should also be some effort by the BLD/Traction Control to get the other front wheel some traction, but in that situation it might be better to back out and choose a better line.

 

[Stormin’ Moorman]

I think the only way you could have one front wheel spinning with the other not moving at all is if you also lose traction with both rear wheels with LSD. There should also be some effort by the BLD/Traction Control to get the other front wheel some traction, but in that situation it might be better to back out and choose a better line.

I'm sorry, I thought the Sahara only had LSD on the rear.

 

[Arterius2]

I'm sorry, I thought the Sahara only had LSD on the rear.

BLD still works on the front.

 

[Sean L]

I'm sorry, I thought the Sahara only had LSD on the rear.

Yes its only on the rear. The front will still use the brakes on a wheel with lost traction in an attempt at getting the other wheel moving though. Probably not as effective as an actual limited slip but so far I haven't noticed any front wheel slip to see how well it works.

 

[D60]

I am not sure exactly but ARB makes a locker that directly swaps in for the sport 44 m220 and the M200. You cannot use rubicon lockers because despite both being 32 spline shafts..the rubicon has different length shafts driver/ passenger..just like the JK.

Of course you will need to get your gears set up correctly again. But from the looks of it you can leave your 3.45 gears.

I regeared to 5.13's and did not have to replace the carrier.

You went from 3.45 to 5.13 and kept the factory carrier? I'm skeptical

 

[intentsrig]

You went from 3.45 to 5.13 and kept the factory carrier? I'm skeptical

Sure did. The only new parts that went in were the ring gear, pinion and pinion bearing because the orginal was stubborn to come off. Had to be pressed off.

I watched him do the whole thing.

Cool pic of 3.45 vs 5.13

 

[AnnDee4444]

Can someone tell me the difference between Lockers vs Anti-spin Differential? I know lockers lock both wheels at the same speeds. Anti spin Differential regulates the speeds, but still provides power to the non spinning wheel. How does this affect off roading? I really don't see much difference in the two. I'm sure someone will beat me down with a matter-of-fact your a dumb-ass answer. But I want to know how it really affects off roading.

Below is a good video explaining the function of a differential.

An open differential is where the wheels are free to turn completely independent of each other (axles are 0% locked together). A locker, or locked axle as it is called in the video, is shown at 2:45, where the left and right axles are locked together 100%. A limited slip differential is one that functions as an open differential under normal conditions, and a partially or fully locked axle when certain conditions are met. It limits the slip between the two axles somewhere between 0% and 100%.



For off road, an open differential can send all the power to a tire with no traction, since it would have the least resistance. The limited slip should eventually figure out that the axles are turning at different rates, and decide to partially or fully lock the axles together, giving the tire with traction some power. A locker sends power to both tires all the time, meaning there is no waiting for the limited slip to "kick-in".

There are many different kinds of limited slip differentials, and all have different properties of what makes them lock and how locked together the axles become.

*edit: removed incorrect information about optional Sahara transfer case

 

[timn1984]

Below is a good video explaining the function of a differential.

An open differential is where the wheels are free to turn completely independent of each other (axles are 0% locked together). A locker, or locked axle as it is called in the video, is shown at 2:45, where the left and right axles are locked together 100%. A limited slip differential is one that functions as an open differential under normal conditions, and a partially or fully locked axle when certain conditions are met. It limits the slip between the two axles somewhere between 0% and 100%.



For off road, an open differential can send all the power to a tire with no traction, since it would have the least resistance. The limited slip should eventually figure out that the axles are turning at different rates, and decide to partially or fully lock the axles together, giving the tire with traction some power. A locker sends power to both tires all the time, meaning there is no waiting for the limited slip to "kick-in".

There are many different kinds of limited slip differentials, and all have different properties of what makes them lock and how locked together the axles become.

I should also mention that AWD vehicles (like the US Sahara option) adds a third differential inside the transfer case, allowing the front and rear axles to turn at different rates as needed. The traditional Wrangler transfer case does not have this differential, and acts like the front and rear driveshafts are locked together (in 4WD).

That was a great video! Love the way they made it so simple. Thanks anndee4444

 

[xtopherm]

A locker is going to give you real 50/50 power to each wheel. The anti spin is going to stop a spinning wheel that has no traction and send power to the other one but it is not immediate and is sort of sporadic. It will go on and off spinning/stopping etc. So not going to have all the traction you really need. Also the anti-spin has clutch packs inside that wear out over time.

This has a good comparison of a real locker vs limited slip vs traction control.


Speaking of traction control, Jeeps BLD combined with the anti-slip is great but for sure is no locker.

An additional consideration is wear - the limited slip differentials do wear out and lose their effectiveness. A fully mechanical locker does not have the same kind of clutch action to wear out. Lockers can break and will certainly wear out with very high milage or extreme use, but they are not designed to have consumable parts like limited slip differentials. The same wear issues apply to the transfer case in the center of the Sahara with the "auto 4wd" function. That transfer case has a clutch pack that wears out with use. Properly maintained and sensibly used lockers are as tough as nails and will last the lifetime of a vehicle.

 

[LLANERO]

Two advantages of LSDs over lockers:
- Don't have to be activated, they are always working.
- Won't affect your steering

Trutrac LSD works with gears instead of clutch pads, so it will last forever.

Also, here's a video of my 2014 JK with trutracs and one wheel on the air:

 

[SecondTJ]

I should also mention that AWD vehicles (like the US Sahara option) adds a third differential inside the transfer case

The Sahara's MP3022 transfer case does not have a center differential. It also uses clutch packs.

 

[AnnDee4444]

The Sahara's MP3022 transfer case does not have a center differential. It also uses clutch packs.

Interesting... I did not know that.

As a side note, I wish Jeep would quit naming their 4wd systems and give real descriptions of what the products actually are. It's ridiculous that there is a Wikipedia page this long dedicated to the variations. Even Jeep's description leaves me with questions:

This two-speed, active full-time system includes a 4H AUTO mode that requires no driver input for any driving conditions. In 4H AUTO, 4WD is automatically engaged and disengaged as needed to maintain traction.

 

[Firestarter]

Also, the anti-spin diff is a reactive system which activates after a loss in traction is detected. Lockers are proactive and one enables them before one anticipates a loss of traction. I’d rather have an LSD than open diffs but generally speaking lockers are better off-road.

The locker, clutch LSD, and helical differential are all proactive. The helical gears that drive the outputs use torque and axial thrust to generate locking action to bind the wheels together. This is why it's always proportional to the weakest wheels available traction as it needs that torque to generate its locking force. The clutch based LSD applies pressure to the outputs which forces the greater traction wheel to receive torque proportional to the clutch pack pressure. The BLD system is reactionary but should compliment the helical differential nicely as it will magnify the braking affect. The only reactionary LSD I've seen is the Eaton G80 locking differential which requires a spun weight to lock against a mechanism that forces a wave gear to apply immense pressure to a clutch pack.

Can someone tell me the difference between Lockers vs Anti-spin Differential? I know lockers lock both wheels at the same speeds. Anti spin Differential regulates the speeds, but still provides power to the non spinning wheel. How does this affect off roading? I really don't see much difference in the two. I'm sure someone will beat me down with a matter-of-fact your a dumb-ass answer. But I want to know how it really affects off roading.

The difference is that a locking differential is able to bias more toque to the wheels with the most grip while the anti-spin differential will be limited. I'm assuming the trac-lok is a clutch based unit as there are clutch rebuild kits for the JL Trac-lok. This means your wheel with the most traction will always receive at least a minimal amount of torque proportional to the clutch packs force plus whatever torque the lower traction wheel can generate. In extreme situations it simply won't be able to drive the greater traction wheel without the BLD system which is reactionary.

Think of an open differential as a water hose with a T-fitting. If you plug one end up the water will flow to the opposite hole but will still transmit its force to your thumb plugging it. Even though the water isn't flowing it's still applying a force.

It's also important to note that an open differential varies the wheel's speed in relation to the carrier. With a stalled wheel the opposite wheel will spin 2x as fast as the carrier is rotated. As the slower spinning wheel spins closer to the carrier's speed so will the opposite wheel. If the carrier is stalled then one wheel spinning 100rpm forward will force the opposite wheel to spin 100rpm reverse. Spin the carrier at 100 rpm and now the reverse wheel is not rotating and the forward wheel is spinning at 200rpm, but both are still spinning 100rpm relative to the carrier in opposite directions.

A locker is going to give you real 50/50 power to each wheel. The anti spin is going to stop a spinning wheel that has no traction and send power to the other one but it is not immediate and is sort of sporadic. It will go on and off spinning/stopping etc. So not going to have all the traction you really need. Also the anti-spin has clutch packs inside that wear out over time.

This has a good comparison of a real locker vs limited slip vs traction control.


Speaking of traction control, Jeeps BLD combined with the anti-slip is great but for sure is no locker.

You have it backwards, a locker biases torque from 0-100%, a helical diff will bias torque based off its TBR (for example a TBR of 3:1 can bias torque 75/25), and an open differential is always 50/50. It's really easy to understand. Lift a wheel off the ground and it cannot generate torque, so the opposite wheel with traction gets the same torque which is nothing. A locker will send 100% of torque to the wheel on the ground since the airborne one simply cannot generate any. A helical diff would act as open sending nothing to the grounded tire as 3 multiplied by 0 is 0.

Which makes the video you posted patently wrong. Also, torque and power are not the same. A stalled wheel receiving torque does not transfer power, so while an open differential biases torque 50/50 always the power flow is can vary wildly. Opposite with a locker, a spinning wheel that receives no torque is not transferring any power, and its power bias varies wildly as well.

 

[Firestarter]

I may be wrong here, but fully locked sends 25% power to each wheel all the time. This is best case scenario when traction is very poor. Otherwise the Rubi has an open diff, which is the best for on pavement. With the Sahara, which has rear LSD, you're sending 50% of the power to front and 50% to the rear. So you could have one front wheel spinning and the other not moving. The rear LSD should make adjustments when one the rear wheels loses traction. So worst case is you have 3 wheels turning. I have a Rubi but the 4x4 system on the Sahara is superior for most people, most of the time. Its just easier.

Actually a fully locked driveline will send 0-100% of torque to each wheel depending on the conditions. Turn on the street and it will overdrive the inside wheel sending far more torque to it. Lift a wheel and the wheel in the air cannot generate torque at all, thus all torque and power must flow to the wheel on the ground. So if you high-center and only 1 wheel is on the ground, all the driveline torque will flow through it until the other wheels are able to generate torque for themselves. Open diffs are 50/50 which means the airborne wheel generating no torque prevents the grounded wheel from receiving any torque.

Just grab any torque wrench and waive it around in the air. You'll notice you need to transmit the torque to something capable of accepting it in order for it to click.

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