Rear locker vs 4L

Therabbittree said:

Fyi the expedition doesnt have a locker it has electronic limited slip. The superduty and f150 get electronic locker . There is a difference. Another forum member was looking at swapping the locker carrier into the expedition rear independant axle center section. It boils down to not easy to do


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Do you have one? I do and can for sure confirm the HD rear end which is the same one used in the max tow HD F150 is a locker.

Calidad said:

Do you have one? I do and can for sure confirm the HD rear end which is the same one used in the max tow HD F150 is a locker.

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I have one, and it's 100% an electronic differential locker. And the manual page I linked in my other post plainly states it's an electronic locker.

Someone is confused.

The Expy has a electronic friction locker by apply pressure to the plates locking the two axles together. It does a good job for what you would use the Expy for. The F-150 has a pin locker. When engaged it slides pins into place to lock the two axles together. The pin lock is a better locker as it can only slip if the pin breaks.


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Fozzy said:

The Expy has a electronic friction locker by apply pressure to the plates locking the two axles together. It does a good job for what you would use the Expy for. The F-150 has a pin locker. When engaged it slides pins into place to lock the two axles together. The pin lock is a better locker as it can only slip if the pin breaks.


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If you go looking at parts.ford.com, I'm pretty certain the friction locker is hydraulically actuated, but electronically controlled. One of the key advantages of this setup over a traditional LSD is that the rotational difference between the axles can be controlled. So when you have it in "snow mode" and turn the steering wheel, the system can use the vehicle speed and steering position sensors to calculate and set the speed differential between the axle shafts. The advantage of this setup over a pin locker is that it maintains the limited slip function, whereas a traditional locking differential is either on or off. The real world advantage is that you can hand the keys to an inexperienced driver*, and just tell them to put it in snow mode and take it slow. The disadvantages are cost, complexity and heat buildup. I'm open to adding "full friction unable to keep the plates locked" once someone reports getting stuck due to this condition.

*or driver unwilling to invest the time to learn all the ins and outs of when to engage disengage a locker and the impact on handling characteristics.

Yes we all know that. But a lot of people do not consider the friction lock a true locker. This debate is all over different forums. And it can and will slip and over heat. Mine has overheated. Unless they have changed something on the new F-150 it is or was a pin lock. Not the same as the Expy. Referring to the 5 post above.


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shane_th_ee said:

I was busy hunting down window stickers, just like you. Like you, every vehicle I saw with the HD tow package also had the 3.73 eLSD (with the 3.73 eLSD listed as a separate option).

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Every 2021 in the greater-Phoenix area with HD Towing has 3.73 non-limited slip (open) differential listed on the sticker

I had to climb a big snow dam plowed into a steep entrance yesterday. Maybe I didn’t “have” to aim dead center for the huge burr the city plow left but I did. Anyway I put it in 4x4 Low rolled the window and observed. Note the 3rd gens you cannot disable braking bias assist in 4WD. Even holding the button only rids the rev limiter. Every second or so the power switched from the passenger tire and my side would start spinning. Then another second would pass and the other side would spin etc. Ultimately it pulled up after a little sweat. I’d say the factory traction control rids the old saying open diffs are 2WD. The power was alternating between the 4 pretty evenly. Albeit switching back and forth. There was no traction to be had as it was all ice and snow, so it was a good showing of what the TC can do in this situation. Now I’d say in deep mud etc the TC probably hits its limit fast. It didn’t help me much in the Dutch a few weeks ago that’s for sure, that’s just too much pressure for braking to overcome.

JExpedition07 said:

I had to climb a big snow dam plowed into a steep entrance yesterday. Maybe I didn’t “have” to aim dead center for the huge burr the city plow left but I did. Anyway I put it in 4x4 Low rolled the window and observed. Note the 3rd gens you cannot disable braking bias assist in 4WD. Even holding the button only rids the rev limiter. Every second or so the power switched from the passenger tire and my side would start spinning. Then another second would pass and the other side would spin etc. Ultimately it pulled up after a little sweat. I’d say the factory traction control rids the old saying open diffs are 2WD. The power was alternating between the 4 pretty evenly. Albeit switching back and forth. There was no traction to be had as it was all ice and snow, so it was a good showing of what the TC can do in this situation. Now I’d say in deep mud etc the TC probably hits its limit fast. It didn’t help me much in the Dutch a few weeks ago that’s for sure, that’s just too much pressure for braking to overcome.

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Typically the ultimate fail in all these systems is the power cut and if or when it takes place. The typical AWD cars being the worst many don’t even have the off button which only just bumps the tire spin tolerances slightly, allowing for more spin before power gets cut. I haven’t had the Expedition in anything yet where that power cut nanny/ tolerance gets found out. One would hope that its far superior ie more tolerant of wheel spin vs the typical AWD SUV that generally become useless cut to idle once wheel spin is happening ie ice/mud/sand etc.

I am sure the ELSD-Locker is "superior" to the F150 Pin-True Locker, though not a strong. The Expy is the more refined, gentrified F150--more feline and less--how do you say? Boorish
IT also may depend on what your definition of "superior" means LOL.

I do not like the idea of the rear overheating. It would be nice if there was a larger diff case to hold extra fluid on the FX4 package and/or the HD towing package (are you listening Ford, your 30 customers want MOAR)!!

I wonder if an earlier than recommended fluid change would help the nannying sensor part of it? And if it is truly locked (even hydrollically) it should not generate additional heat (if really providing no slippage), unless the electric motor holding it clamped gets nervous from hanging on so long?

Q: Does the F150 w/pin locker also have limited slip in 2-4wd like the Expys?

“Superior...but not as strong”. I am really skinny for a fat guy. It’s plenty good for soccer moms and light duty. I use it way more than four wheel drive. But it is only a simulated locker. Add oversized tires and extreme condition and you will make it slip and over heat especially with prolonged use. And it defaults to an open diff. So as a locker, not so much. As a limited slip multi mode grocery getter, probably can’t beat it.


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