Factory Rear Locker addition?

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JCBIII

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Got stuck on an Icy hill yesterday, 4wd was on, but the limited slip wasn't limiting LOL. I didnt even realize it didnt have the rear locker when i bought it. Every Ford ive had in the last 10 years has been an FX4 and had the locker.

Anyways. is it possible to add the factory parts and make the knob on the dash work like the fx4? (i have a 2017 by the way) or is it better off just to get something aftermarket? Im not opposed to finding a rear diff in a junk yard if needed, but I dont know what the commonalities and crossable parts on these models are.
 

JasonH

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Nearly anything is possible with sufficient funding. I think what you're really asking is whether it is cost effective to install the stock ELSD. My understanding from previous discussions on this forum is that it is not, in part because of the electronically activated components. Detroit Truetrac is a commonly referenced, more cost effective aftermarket option.
 

LokiWolf

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Nearly anything is possible with sufficient funding. I think what you're really asking is whether it is cost effective to install the stock ELSD. My understanding from previous discussions on this forum is that it is not, in part because of the electronically activated components. Detroit Truetrac is a commonly referenced, more cost effective aftermarket option.
This! No factory "Locker" option. Only limited slip, and it was mechanical in the 3rd Gens. Do you even have the LSD?
 

JasonH

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This! No factory "Locker" option. Only limited slip, and it was mechanical in the 3rd Gens. Do you even have the LSD?
Mine doesn't have the LSD. You are correct regarding the 3rd gen being mechanical, not electronic. I think the OEM Ford is a mechanical clutch type for 3rd gen. I'm actually looking into regearing 3.31 - > 3.73 and truetrac for mine. I got a quote for a regear and LSD install for $2,500. I've been hesitant to do any beach or snow driving because I've gotten stuck twice, both times in mud. The truck acquitted itself well in light snow with my all terrains, but not sure how it would do with anything in ski areas. But I think those roads get plowed anyway. Now that the truck is getting higher in miles and the extended warranty is gone, I'm not so resistant to modding it.
 

LokiWolf

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Mine doesn't have the LSD. You are correct regarding the 3rd gen being mechanical, not electronic. I think the OEM Ford is a mechanical clutch type for 3rd gen. I'm actually looking into regearing 3.31 - > 3.73 and truetrac for mine. I got a quote for a regear and LSD install for $2,500. I've been hesitant to do any beach or snow driving because I've gotten stuck twice, both times in mud. The truck acquitted itself well in light snow with my all terrains, but not sure how it would do with anything in ski areas. But I think those roads get plowed anyway. Now that the truck is getting higher in miles and the extended warranty is gone, I'm not so resistant to modding it.
The LSD question was directed at the OP.

I think the Truetrac would be a great upgrade!
 

2010ELExpy4x4

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Were you in 4H or 4L?
Traction control doesn't work in 4L.
I am old school so tough spots called for 4L. Until we were out and had to climb nasty hill with offset
mounds and valleys. Tried 4L got stuck, put in 4H it powered right up, it applies brake to loose traction or airborne wheels. Still wouldn't mind some lockers though.
 

JExpedition07

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Were you in 4H or 4L?
Traction control doesn't work in 4L.
I am old school so tough spots called for 4L. Until we were out and had to climb nasty hill with offset
mounds and valleys. Tried 4L got stuck, put in 4H it powered right up, it applies brake to loose traction or airborne wheels. Still wouldn't mind some lockers though.
I swear it was the weight of the cast iron over the front end on the 5.4. My 07 never got stuck in anything. Nothing I’ve driven since has been as good in snow.
 

mjp2

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Mine doesn't have the LSD. You are correct regarding the 3rd gen being mechanical, not electronic. I think the OEM Ford is a mechanical clutch type for 3rd gen. I'm actually looking into regearing 3.31 - > 3.73 and truetrac for mine. I got a quote for a regear and LSD install for $2,500. I've been hesitant to do any beach or snow driving because I've gotten stuck twice, both times in mud. The truck acquitted itself well in light snow with my all terrains, but not sure how it would do with anything in ski areas. But I think those roads get plowed anyway. Now that the truck is getting higher in miles and the extended warranty is gone, I'm not so resistant to modding it.
TrueTrac is a great option. I don't spin tires anymore unless I want to.

If you're running stock size tires you'll be very happy with 3.73s but if you're running taller consider 4.10s. It's a massive leap from where you are but you and the truck will both be happier for it. With heavy 35" tires my truck cruises effortlessly at highway speeds with the 4.10s. Even my wife commented on how much better it drives.
 

LokiWolf

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TrueTrac is a great option. I don't spin tires anymore unless I want to.

If you're running stock size tires you'll be very happy with 3.73s but if you're running taller consider 4.10s. It's a massive leap from where you are but you and the truck will both be happier for it. With heavy 35" tires my truck cruises effortlessly at highway speeds with the 4.10s. Even my wife commented on how much better it drives.
You have a 5.4, he has a 3.5TT, with MUCH more torque, and it would have zero issue effortlessly turning 35’s with 3.73’s. 4.10 would be way too low, and unneeded.
 

mjp2

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You have a 5.4, he has a 3.5TT, with MUCH more torque, and it would have zero issue effortlessly turning 35’s with 3.73’s. 4.10 would be way too low, and unneeded.
Noted. I forget how powerful that turbo engine is.
 

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