Swapping out a new shift lever and I saw this broken part sitting next to base:



I found where it broke off of from online photos:



The wheel rides atop the "knuckle" profile corresponding to the different gear positions, with a tension spring ensuring the wheel maintains contact.

Without this piece, the shifter seems to shift fine with the gear selector firmly "notched" in position and all indicators show accurate position, so what exactly is the purpose of this pivoting "arm"?

I can pull out the broken remains out of the pivot hole with ease as their is very little tension in the spring. It doesn't appear this is a serviceable part, meaning I would have to purchase a whole shifter assembly (which includes shift handle and grips, which I had just replaced with new) with a street price ~$140. I'm not sure I need to replace it as I haven't seen any lost functionality...

 

Does it still prevent shifter movement without the release button pressed?

 

Yes, but that function is handled by a flat bar down at the base which is connected to a rod that is physically depressed by the front grip button (lever). I noticed that functionality when I was replacing the actual shift lever and couldn't get the shifter out of park with the shift lever removed unless I depressed the rounded top of the the rod that rides inside the shift lever stub.

 

Does it have anything to do with gear selector on the dash or shifter base?

 

From this inquiry, I went forth and scrutinized all indicators and functions thoroughly, and as far as I've verified, all gauge indicators correctly show shifter position: both the bottom P-R-N-D-2-1 row as well as the optional right SelectShift column.

So this little doodad's purpose has got me stumped as there is no lost functionality that I can ascertain. What I haven't yet tried is attempting to start in any of the drive gears (R-D-M-2-1)...

 

I've been driving with mine broken off like that for 2 years. The only function Is the slight feedback you can feel from the shifter as it moves across each gear position.

 

I think I remember that same piece had broken off my 2011 but at the time I didn't know where it broke off from and didn't bother to figure it out as I didn't notice anything wonky.

As far as physical feedback of gear position, I still have a very pronounced gear "detent" feel, both physically and audibly, at each gear as I'm shifting without that piece; that was the first thing I checked after thinking with those ridges that it may be to provide tactile feedback. Perhaps it was designed to enhance that feedback in some way.

At this point it seems the real answer can only come from a Ford engineer familiar with the shifter/transmission controls...

 

As I was driving home from work and started testing an epiphany that dawned on me after I posted earlier that perhaps it was designed to enhance feedback: This component is instead designed to assist moving the shifter into the closest gear slot whenever the driver releases the shifter. Without this piece, it seems I can place the shifter in between gears and have it stay there with relative ease. There are no attached sensors or electrical contacts, so it isn't used for any position indication, which I've proven earlier. And the tension spring is of a large diameter to suggest it exerts a lot of force to the arm's wheel onto the rounded "knuckle" profile. With two of my 12th gen trucks having the arms broken off, and a third reported by D_BRASO, the anecdotal evidence reveals that the design is not sufficiently engineered to withstand countless shifts through the years, so as the plastic ages and fatigues, it eventually breaks off due to the high spring tension.

That's my theory at least...