In all my past vehicles with some form of limited slip differentials, they have been either clutch pack or Torsen style. I have a 2025 F150 on order, and it is coming with the locking unit. Am I correct in assuming that this means a switch to mechanically lock the two axle halves together? And if so, when it is not locked, is it an open unit, or does it still have some form of limited slip system?

 

Great question. There have been many conversations about this and never really a solid answer for me.
I assume it is open [one wheel] unless it is a locking diff or [locked]

 

Correct on both counts, electrically engaged, no limited slip when unlocked.

 

Open differential. Not sure what you mean by one wheel, but no such thing exists.

 

"one wheel peel" is definitely what happens when you try and enter traffic while turning 90 degrees left or right when in 2H! I've started leaving the truck in 4A around town, it performs so much better than in 2H. I'll leave that for long highway trips from now on.

 

can you provide an exact definition of
open then?
Im not sure what open means, been
asking that for a while now on this forum
thanks!

 

An "OPEN" differential refers to one where there is no provision to keep the left and right axle halves turning, or providing torque to the rear wheels, at the same rate. Each axle half can freely turn at different speeds, for instance when cornering. The downside of this type is that when the driveshaft is applying torque to the differential, if one wheel has much less traction than the other, it is the one which starts rapidly spinning and wasting energy, if too much throttle is applied for the situation. Think of an open door, that is a door that is not latched closed. An open differential has no provision to try to latch the two axle halves together. Some differentials provide some amount of latch of the two halves, either thru friction of clutch plates, or by gearing leverage, such as a Torsen style. Then, there is the "locking" differential, which uses a switched solenoid to mechanically lock/latch the two halves together.

 

Yep, open differential = ‘one-wheel wonder’ moniker. Equal torque to both rear wheels, issue being when one wheel has limited traction, torque to the opposite wheel is equally low. That said, our trucks have a brake-based limited slip system, so the truck will apply the brakes to the spinning wheel to keep free-spinning in check.

 

Thanks, seems like there should be a different term other than "open" or "regular" . or " non locking"

 

Probably are many excellent videos on YouTube explaining differentials. As far as nomenclature, differentials and their types have been around for many years, some have been descriptive names, some have been proprietary names or bastasdized from proprietary names.