Adding aftermarket Limited Slip Differential

[Blu21]

Hi, new to the forum. Just bought a 2021 Expedition Platinum that does not have the eLSD option. What's the conventional wisdom on the best way to add a limited slip rear? Can the OEM be installed as an aftermarket add on? I've seen some mentions that this might be hard to do, involve a different axle, different electronics, etc. I've also seen reference to the Eaton Trutrac as a possible option. Also, any idea on cost to have one installed?

If it helps the window sticker says I have the "non-elsd axle" but I'm not sure if that's the 3.13 or the 3.73. The sticker also says I have the "trailer tow prep package" and I'm not sure if that's the HD trailer tow package or not. If it does have the HD tow package, that sure an odd way to phrase it on the sticker. Any help clarifying that is appreciated.

Sorry if this is all posted somewhere already. All I could find in the searches were debates over the eLSD and the HD tow package.

Thanks for any advice you can offer!

 

[Blu21]

Oh, and one more thing that may matter: this Expedition was originally made for the Canadian market.

 

[DieselMonk]

The market doesn’t matter. The eLSD talks to other modules as it sets up with the terrain management system, the ABS, etc… So things would have to be programmed as well which is not easy at all. I think it’s better to get a different Expy that has it already installed. The eLSD is the one of the best options to have. It acts as a computer controlled LSD which you can mimick a rear locker by tighten the clutch packs full tilt with a press of a button.
I think the rear end has to be 3.73 and of course the front too. Not sure if a regular Detroit true trac will work.
If your Expy has HD trailer tow, it has the right axle and correct 3.73 gearing front rear. If you don’t have that HD trailer tow, you look at 3.73 front, 3.73 rear, that HD rear axle and an LSD if it fits.

My SPP has the eLSD and that thing on winter tires is a weapon for daily driving. Where others spin wheels, I am already long gone. It would be a dealbreaker for me buying an Expy not having that eLSD. Keep in mind I am having a very “spirited” driving style, mostly on road and some mild off road.

 

[Fizzy]

"trailer tow prep package"

This is not the HD Tow package - it's just the tow electrical plugs (7 pin, 4 pin) at the back under the removable bumper cover.

You're not going to be able to add eLSD for all the reasons @DieselMonk mentioned, and many more he didn't, including spending a small fortune - move on from the idea.

 

[Blu21]

Thanks everyone. Anyone else know if one of the non-OEM options (Trutrac or others) can be swapped in or if I'm going to run into similar problems with that approach? If so, I'll have to just make do with good winter tires. Thanks again.

 

[DieselMonk]

If so, you need the big rear differential with the 3.73 and that comes only on the HD trailer tow. That means you need to change the front too, speedo reprogramming etc. The small normal diffs are too small to fit anything else inside.

Looks like you got 2 options. Either trade the truck in and get a proper spec’d one or forget about it all together.