Once and for all...max tow package...ELSD? E-locker? Locker?

[carymccarr]

What is it?

 

[Fozzy]

What is it?

Unless they changed something on the Expy it should be like the F-150
Your window sticker should say ELSD. It is a “locker” as it binds both wheels together. It is a “E-locker” as it’s electronically engaged and activated. It works like the Eaton locker. Some may say it’s limited slip as well. But that is controlled by the advanced trac system. Not clutches and springs in the diff.





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[shane_th_ee]

Yes, it's a big change from the F-150. It's actually an electronically controlled, hydraulically actuated limited slip differential with locking mode. Take a close look at the parts drawing linked below and look for the hydraulic pump mechanism:

https://parts.ford.com/shop/en/us/transmission/powertrain-engine-parts/differential-assy-6513577-1

Here's the F-150:
https://parts.ford.com/shop/en/us/transmission/powertrain-engine-parts/differential-assy-6518391-1

At the cost of complexity and price, the idea is to give you the best of all possible worlds. The hydraulic pump design lets the vehicle control the amount of slip within the differential. As opposed to a normal limited slip differential which is mechanically fixed (wheels spin independent until one is going faster than the other by some fixed ratio). And you still get a locking mode, which you don't get in a traditional limited slip. But of course, with a traditional e-locker, there is no limited slip mode. The rear drive shafts are locked or they spin independently with no maximum speed difference between the two.

 

[JExpedition07]

Shane is correct

 

[Fozzy]

Is there friction plates that are pushed together? I see the actuator ring, but what does it push against? That would explain why TFL had drive mode and rear locking problems.


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[LokiWolf]

Is there friction plates that are pushed together? I see the actuator ring, but what does it push against? That would explain why TFL had drive mode and rear locking problems.


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TFL issues were that it disables when you turn the Truck off. Andre turned Truck off and got out, then got back in and forgot to Turn it back on. He got blasted for it too!!!


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[LokiWolf]

Yes, it's a big change from the F-150. It's actually an electronically controlled, hydraulically actuated limited slip differential with locking mode. Take a close look at the parts drawing linked below and look for the hydraulic pump mechanism:

https://parts.ford.com/shop/en/us/transmission/powertrain-engine-parts/differential-assy-6513577-1

Here's the F-150:
https://parts.ford.com/shop/en/us/transmission/powertrain-engine-parts/differential-assy-6518391-1

At the cost of complexity and price, the idea is to give you the best of all possible worlds. The hydraulic pump design lets the vehicle control the amount of slip within the differential. As opposed to a normal limited slip differential which is mechanically fixed (wheels spin independent until one is going faster than the other by some fixed ratio). And you still get a locking mode, which you don't get in a traditional limited slip. But of course, with a traditional e-locker, there is no limited slip mode. The rear drive shafts are locked or they spin independently with no maximum speed difference between the two.

This. It is not the same as the 150 locker.


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[AKentPhoto]

Great info here...
Thanks for clarifying. I was beginning to think it was all software but I'm glad to hear there is something physically trying to lock back there.

I did find this random video...

 

[shane_th_ee]

TFL issues were that it disables when you turn the Truck off. Andre turned Truck off and got out, then got back in and forgot to Turn it back on. He got blasted for it too!!!


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Andre does not understand how 4x4 systems actually work, let alone the nuances of one as complex as the one in the Expedition. It has a soccer mommy mode (just spin the drive mode dial). But it also has manual control functions for those who take the time to learn about the systems and how/when to use them. Andre just got in and mashed some buttons and the results while disappointing should not have been unexpected. Which is exactly how came to snap the driveshaft in an F-150...

 

[Fozzy]

I am very interested in how this works still. I have a Can-Am SxS. In the past the front diff was called a Visco Lock. Nicknamed the Crisco lock. You would need to spin the tire for multiple times before it engages. You would be stuck or rolled over before it did it’s job. They changed it to a Smart Lock that has drive modes. It works by the actuator pushing plates together. Different pressures make different drive modes. It claims to have a full lock at the max pressure. People running large tires and big HP have walked through this locking mechanism since there is no actual pins locking the two together. Apparently it gets worse the more you slip it. Would this be the case on the Expy? I would rather have a open diff with pin locks. But I only use the full lock to pull the boat out of the water so I’m not worried about breaking it.


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[shane_th_ee]

I am very interested in how this works still. I have a Can-Am SxS. In the past the front diff was called a Visco Lock. Nicknamed the Crisco lock. You would need to spin the tire for multiple times before it engages. You would be stuck or rolled over before it did it’s job. They changed it to a Smart Lock that has drive modes. It works by the actuator pushing plates together. Different pressures make different drive modes. It claims to have a full lock at the max pressure. People running large tires and big HP have walked through this locking mechanism since there is no actual pins locking the two together. Apparently it gets worse the more you slip it. Would this be the case on the Expy? I would rather have a open diff with pin locks. But I only use the full lock to pull the boat out of the water so I’m not worried about breaking it.


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https://patents.google.com/patent/US20170089439A1/en

 

[Fozzy]

https://patents.google.com/patent/US20170089439A1/en

Thanks, I can’t get it to zoom open on my phone to get a good look. But I can see what is doing. It looks good enough for grocery getters.


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[Fozzy]

Just finished reading the diff patent application. Very good read. Noticed one of the patent citations is from the Can-Am. Hahahaaa


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[carymccarr]

https://patents.google.com/patent/US20170089439A1/en

So there IS a mechanical clutch that locks the differential.

Interesting. Thanks for linking to that.

 

[LokiWolf]

Andre does not understand how 4x4 systems actually work, let alone the nuances of one as complex as the one in the Expedition. It has a soccer mommy mode (just spin the drive mode dial). But it also has manual control functions for those who take the time to learn about the systems and how/when to use them. Andre just got in and mashed some buttons and the results while disappointing should not have been unexpected. Which is exactly how came to snap the driveshaft in an F-150...

Truth! Their videos still give more real world info than most others.

My wife will just spin the dial to where I tell her, but yes, I will use the buttons and adjust appropriately.

Left on its own the system does a pretty decent job.


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[carymccarr]

Truth! Their videos still give more real world info than most others.

My wife will just spin the dial to where I tell her, but yes, I will use the buttons and adjust appropriately.

Left on its own the system does a pretty decent job.


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What buttons?


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[LokiWolf]

The 2H, 4A, 4L, and Lock Buttons around the Mode selector...

For example, Normal defaults to 2H, but you can turn on 4A, and the opposite is true for Sport. It defaults to 4A, but you can switch back to 2H, and turn off TC to get a little wheel spin.

 

[carymccarr]

The 2H, 4A, 4L, and Lock Buttons around the Mode selector...

For example, Normal defaults to 2H, but you can turn on 4A, and the opposite is true for Sport. It defaults to 4A, but you can switch back to 2H, and turn off TC to get a little wheel spin.

Hmmm. I have HD/max trailering package on my Navi and there are no buttons that I’ve seen.

 

[Fozzy]

This is what the Expy looks like.



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[LokiWolf]

Hmmm. I have HD/max trailering package on my Navi and there are no buttons that I’ve seen.

Navi doesn't get the buttons, but you get additional modes us Expy people don't have. Those additional modes give you the combos we can get by using the buttons. Page 217 of your manual.