rear differential locked

I am curious if Ford could do a pin system on the Expy? Perhaps maybe even a Torsen rear may be a better solution? There are obvious differences in axle tubes vs CV axles, but they run a Torsen front end to lock the Tremors. I am sure glad I optioned the locker, in May I am installing a stage 2 Whipple on my 5.0L V8. With 800 horsepower the locker is my only hope for a halfway decent launch. I’ll report back if my 5.0 starts snapping pins!! lol.

JExpedition07 said:

The issue with the Expedition is that they are really calling an LSD a “locker”. The locker in my F-150 operates off an electromagnetic ball ramp mechanism that pushes several (10) locking pin bars into matching holes on the back of the side gear housing, which locks the axle. Very robust (and good for burnouts!). The Expedition not so much, it’s a clutch based system. F-150s electronic locking axle operation below, as you can see it is a true “locked” condition. No clutch magic, damn marketing department at Ford.
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Hey @JExpedition07 Nice to see you! Thanks for the pictures to go along with what I explained on Monday! Ford does call it a locker in the manual, which is totally inaccurate, but hey that is why forums like this exist.

terr5178 said:

I just read similar issues was fixed by adding fluid to diff some limited slip fluid. Not sure the name but was in a post on this site

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NO, DO NOT ADD Friction Modifier to the ELSD Diff. Only use the fluid specified by ford. That was a thing that was done on the previous gen mechanical LSD from Ford, and pretty common.

I was Incorrect in this statement. - Looks like with a complete refill you need to add 4oz of the XL3 Friction Modifier. ONLY when doing a complete refill, do not add additional.

LokiWolf said:

NO, DO NOT ADD Friction Modifier to the ELSD Diff. Only use the fluid specified by ford. That was a thing that was done on the previous gen mechanical LSD from Ford, and pretty common.

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I guess they require 4.0-5.0 oz of XL-3 friction modifier in my 2018. It was mentioned in the specifications page of the rear diff!

Soliyou said:

I guess they require 4.0-5.0 oz of XL-3 friction modifier in my 2018. It was mentioned in the specifications page of the rear diff!

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Interesting! You are 100% correct. I had read the non LSD stats. I thought the ELSD did not need it. With the electronic clutches it didn't makes sense...but hey here we are.

I changed the rear differential fluid for my 2014 RAM 1500 when it hit 90k miles. And it looked really bad. The front differential fluid and the transfer case fluid, however, both look new to me. But I replaced them anyway.

JExpedition07 said:

I am curious if Ford could do a pin system on the Expy? Perhaps maybe even a Torsen rear may be a better solution? There are obvious differences in axle tubes vs CV axles, but they run a Torsen front end to lock the Tremors. I am sure glad I optioned the locker, in May I am installing a stage 2 Whipple on my 5.0L V8. With 800 horsepower the locker is my only hope for a halfway decent launch. I’ll report back if my 5.0 starts snapping pins!! lol.

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For daily driving and control in varying conditions the ELSD FAR outperforms the ELD in the 21+ 150. How do I know, I own both. I would much rather drive the Expedition in the average slick/bad weather than the truck. For 2 major reasons. General weight distribution. The Expedition is better balanced, even with the 800-900 pounds of tools I keep in the bed of the 150 regularly. The 2nd and primary reason is the ELSD. It just works! If there is slip in the rear, it just does it's job, then back to open. 2 wheels powering when it needs it, and open when it doesn't. The locker in the 150 is GREAT off road when I am on that dirt/gravel overlanding path, but not at higher speeds where the ELSD shines. The ELSD is tied to the ABS, and stability control, and the brake biased traction control. They all work together, and under most conditions, do GREAT.

It's a 2024 so I assume it's under warranty right? Why don't you just take it to a dealer and let them figure it out? Obviously don't say anything about trying to do a burnout but your truck is under warranty.

LokiWolf said:

For daily driving and control in varying conditions the ELSD FAR outperforms the ELD in the 21+ 150. How do I know, I own both. I would much rather drive the Expedition in the average slick/bad weather than the truck. For 2 major reasons. General weight distribution. The Expedition is better balanced, even with the 800-900 pounds of tools I keep in the bed of the 150 regularly. The 2nd and primary reason is the ELSD. It just works! If there is slip in the rear, it just does it's job, then back to open. 2 wheels powering when it needs it, and open when it doesn't. The locker in the 150 is GREAT off road when I am on that dirt/gravel overlanding path, but not at higher speeds where the ELSD shines. The ELSD is tied to the ABS, and stability control, and the brake biased traction control. They all work together, and under most conditions, do GREAT.

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I have both as well and since my wife goes hunting with me now, we routinely take them both off road to hunt (though the Expedition is the real hunting wagon). I can only recall needing to punch the "Lock" button twice on the Expedition in four seasons, even though it's been in a lot of dicey conditions. The various offroad drive modes, especially mud and ruts work the ELSD and transfer case clutches to keep the torque at the correct wheels to maintain forward momentum.

The F150 with the binary open/locked "locker" system, not so much. When things get slippery, 4H helps, especially at higher speeds; but, when the going gets slow in the swamps, the rear has to be locked frequently to keep from spinning 1 front and 1 rear wheel; then, you have to be careful to open it back up when you're making turns. It's tricky when you're in a muddy situation that also requires tight turning. Not to mention the 10" longer wheelbase and extra 800lbs (it's a PowerBoost).

LokiWolf said:

For daily driving and control in varying conditions the ELSD FAR outperforms the ELD in the 21+ 150. How do I know, I own both. I would much rather drive the Expedition in the average slick/bad weather than the truck. For 2 major reasons. General weight distribution. The Expedition is better balanced, even with the 800-900 pounds of tools I keep in the bed of the 150 regularly. The 2nd and primary reason is the ELSD. It just works! If there is slip in the rear, it just does it's job, then back to open. 2 wheels powering when it needs it, and open when it doesn't. The locker in the 150 is GREAT off road when I am on that dirt/gravel overlanding path, but not at higher speeds where the ELSD shines. The ELSD is tied to the ABS, and stability control, and the brake biased traction control. They all work together, and under most conditions, do GREAT.

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Not a surprise given a true locker does not excel on pavement, it is really for when you have severe axle articulation etc. Ford probably figures the use case of the F-150 (being on job sites etc) needs a “go or no” condition vs the in between. To be honest the Expedition is just better in snow period. My open diff 2007 Expedition EL had more traction in a straight line in 2WD than the F-150 with the rears locked. The F-150 is a 400 HP V8 with no weight over the rear, it just blows off the rear tires in any rain or snow. The Expedition has the weight over the rear and behaved much better in snow. The Expedition also never got squirrelly lane changing like the F-150 does in 2 wheel drive.