I got a 21 STX with the electronic locking rear diff. Can I swap in a traction lock rear diff without having computer issues ? Does the electronic lock come into play for any calibrations ? A full time locking diff is the only thing this truck is missing. I already swapped the small mirrors for the larger towing mirrors. Since all the trucks in the fleet at work are fords, we have the software to program the computer so my buddy reconfigured the system for me when I added the tow mirrors. Plus got the mirrors at the discounted fleet rate from the dealership.

 

I have a Trutrac in both my 2020’s

 

What type of differential are you specifically looking for? Helical and clutch-driven limited-slip differentials will work fine, front or rear. Ford even sells a special Torsen helical gear driven limited-slip for the front of the F-150. I think both Torsen and Eaton Truetrac have options for the rear.

Auto-lockers like the Detroit will probably work, but may create some unusual handling, especially in the rear. A spool is technically possible, but not recommended.

Note that the 9.75 semi-float and 9.75 3/4-float carriers are not cross-compatible without significant modification. They are a different spline count. The semi-float 9.75 (as well as the Super 8.8) is 34 spline, but the 3/4-float is 35 spline.

I believe all 2021+ F-150s use a 31-spline front 8.8.

 

I don't do any off-roading. I want it for winter driving and street driving. I have a bit of a lead foot and the truck will do a one wheel peel when I am getting on it.

 

When it was installed was it plug and play or did it have to be shimmed ?

 

When I had TrueTracs installed on my 2011 and 2014 I bought a package of miscellaneous shims, just in case. We didn't need them. We just put the stock side shims back in the original locations.

 

I swapped a Ford trac-lok into the 9.75" semi-float rear axle on my 2021 and I didn't run into any issues. Do you know which rear axle your truck has?

https://www.f150forum.com/f129/diffe...9/#post7024088