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I know, another Locker vs anti spin Diff question

Arterius2

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I read what you wrote. " Even if the front wheels are spinning. You will still get 50% traction in the rear, because front and rear are locked solid." That's not what happens. A part-time 4wd system cannot send torque to an axle that cannot develop it.

Watch this video.

Wtf man, I was not talking about a locking differential on the axle. I was talking about 4WD which is essentially locking the front and rear axles with a solid drive shaft.

You seem to be confused with terminology being used here and your statements seem to contradict itself.

Again, I don’t think you understand the difference between AWD and 4WD.

So no, you did not read what I wrote.
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aldo98229

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Those who haven’t used Selec-Trac some times have a hard time figuring what it is, so they will say it is “like AWD.” This is half correct.

In Auto mode Selec-Trac does work like AWD in that you don’t have to do anything; the system automatically engages and disengages the front axle.

However, a feature that makes Selec-Trac unlike AWD is that it also has a part-time 4WD mode (both 4Hi and 4Lo), which works like any other Wrangler 4WD system: it engages the front and rear axles and locks them together at the transfer case. In part-time mode Selec-Trac can only be used on loose or slippery surfaces, just like Command-Trac or Rock-Trac.
 

Arterius2

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Those who haven’t used Selec-Trac some times have a hard time understanding what it is, so they just say it is “like AWD.”

In Auto mode Selec-Trac does work like AWD in that you don’t have to do anything; the system automatically engages and disengages the front axle.

However, a feature that makes Selec-Trac unlike AWD is that it also has a part-time 4WD mode (both 4Hi and 4Lo), which works like any other Wrangler 4WD system: it engages the front and rear axles and locks them together at the transfer case. In part-time mode it can only be used on loose or slippery surfaces.
I was trying to explain to him that 4WD locks the front and rear axles together, unlike AWD, where front and rear axles are essentially connected with an open differential. That solid mechanic link between the front and rear axles in 4WD allows one/both front wheels or one/both rear wheels to slip completely and still be able to transfer torque to the other axle that still has traction.

Plenty of videos demonstrating this concept online where a 4WD vehicle is placed on two rollers on the front or rear wheels, and still be able to drive off it.

Obvious if one or more front wheel and one or more rear wheel slips completely at the same time, a 4WD system will have zero reaction, and that is when front and rear axle lockers come in.

Let’s take selec-trac out of the equation first and make sure everyone is on the same page thus far. Lol
 

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I think it is you that is confused. Perhaps if you actually read what I wrote then you might understand.

The center differential or part-time transfer case acts the same as any other differential. Open it behaves in a 50/50 split. If the front axle generates no torque, then the rear axle will get no torque. When locked, it will BIAS torque to the axle with the traction.

Open diff = equal torque at both OUTPUTS (axle or wheels) which is 50/50
Locked diff = biased torque based off the resistance an output receives.

I cannot be more clear. YOU CANNOT DEVELOP OR TRANSFER TORQUE WITHOUT AN OPPOSING FORCE. That opposing force is traction.

So, on the rollers, those wheels develop little to no torque and all the torque flows to the wheels that can develop it.

Stop making up in your head what you think I'm saying, because I never stated that a locked center diff or part-time 4wd system behaves like an AWD system. With an open center differential, both axles are limited to the torque of the weakest one because they receive equal torque (50/50). Locking the center differential allows the front axle on rollers to not develop any torque, yet still bias the engines torque to the rear.

Wtf man, I was not talking about a locking differential on the axle. I was talking about 4WD which is essentially locking the front and rear axles with a solid drive shaft.

You seem to be confused with terminology being used here and your statements seem to contradict itself.

Again, I don’t think you understand the difference between AWD and 4WD.

So no, you did not read what I wrote.
 

Arterius2

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I think it is you that is confused. Perhaps if you actually read what I wrote then you might understand.

The center differential or part-time transfer case acts the same as any other differential. Open it behaves in a 50/50 split. If the front axle generates no torque, then the rear axle will get no torque. When locked, it will BIAS torque to the axle with the traction.

Open diff = equal torque at both OUTPUTS (axle or wheels) which is 50/50
Locked diff = biased torque based off the resistance an output receives.

I cannot be more clear. YOU CANNOT DEVELOP OR TRANSFER TORQUE WITHOUT AN OPPOSING FORCE. That opposing force is traction.

So, on the rollers, those wheels develop little to no torque and all the torque flows to the wheels that can develop it.

Stop making up in your head what you think I'm saying, because I never stated that a locked center diff or part-time 4wd system behaves like an AWD system. With an open center differential, both axles are limited to the torque of the weakest one because they receive equal torque (50/50). Locking the center differential allows the front axle on rollers to not develop any torque, yet still bias the engines torque to the rear.
Well yes. I agree.

What I don’t understand is why you are keep arguing with me and repeating the same stuff over and over again

I basically wrote what you wrote but in one easy to understand paragraph.
 

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Firestarter

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That's also how Chevy's autotrac transfer case works. The rear axle will always get the torque it can develop, and based off wheel speed sensors and demanded torque the transfer case can squeeze the clutches into biasing torque to the front differential.

But it's limited to physics. If the front end doesn't have any traction, then even if it's fully locked it cannot "send" torque to it. It can only spin the wheels.


Those who haven’t used Selec-Trac some times have a hard time figuring what it is, so they will say it is “like AWD.” This is half correct.

In Auto mode Selec-Trac does work like AWD in that you don’t have to do anything; the system automatically engages and disengages the front axle.

However, a feature that makes Selec-Trac unlike AWD is that it also has a part-time 4WD mode (both 4Hi and 4Lo), which works like any other Wrangler 4WD system: it engages the front and rear axles and locks them together at the transfer case. In part-time mode Selec-Trac can only be used on loose or slippery surfaces, just like Command-Trac or Rock-Trac.
 

Firestarter

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I didn't see you write that at all.

You claimed my statements are contradictory, yet haven't shown a single one.
You claimed that I'm confusing AWD and 4WD
You claimed "An open front+rear diff in 4WD is still 50/50 front and back. But think of it having a centre diff locker because the drive shaft is basically a solid mechanical connection."

What I don't understand is why state I'm confusing AWD and 4WD if you agree? You acknowledged I've been repetitive and kept stating the same thing over and over again.

So you no longer think that 4WD is "still 50/50 front and back?"

What I don’t understand is why you are keep arguing with me and repeating the same stuff over and over again

I basically wrote what you wrote but in one paragraph.
 

aldo98229

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That's also how Chevy's autotrac transfer case works. The rear axle will always get the torque it can develop, and based off wheel speed sensors and demanded torque the transfer case can squeeze the clutches into biasing torque to the front differential.

But it's limited to physics. If the front end doesn't have any traction, then even if it's fully locked it cannot "send" torque to it. It can only spin the wheels.
I don’t know the Chevrolet system.

The Jeep system uses a clutch pack in the center that allows slippage in Auto mode, but locks front to rear in part-time model, just like any other Jeep transfer case.
 

Firestarter

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I don’t know the Chevrolet system.

The Jeep system uses a clutch pack in the center that allows slippage in Auto mode, but locks front to rear in part-time model, just like any other Jeep transfer case.
Yeah, they sound identical in operation. Having it in a silverado, I hated it. Little slip in the wet and it would clunk and go very abruptly.
 

aldo98229

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Yeah, they sound identical in operation. Having it in a silverado, I hated it. Little slip in the wet and it would clunk and go very abruptly.
Not Jeep's Selec-Trac: it works immediately, quietly and smoothly.

You barely hear the rear tires slip for a split second when 4WD engages seamlessly and the Jeep continues on like a champ.
 

Firestarter

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Not Jeep's Selec-Trac: it works immediately, quietly and smoothly.

You barely hear the rear tires slip for a split second when 4WD engages seamlessly and the Jeep continues on like a champ.
I'm sure the tuning is different. I was speaking about mechanical operation. Though, my Z71 was an 06 and had a clunk auto locking rear differential as well as a 50mph 1st gear. The newer Chevy models will lock up the clutch if you stab the throttle.
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