Undercarriage inspection mystery NUT?
 

Was doing undercarriage inspection and noticed a nut laying in the front in between plastic.

I know this is long shot but does anyone recognize this nut and it’s proper placement?

It has three slots running horizontally through threads. Also it has a washer that rotates but attached to nut.

I have looked over the car and do not see any studs missing a nut .

My car has not been worked on besides dealer they aligned the fender was told wheel liner removed bolt loosened fender realinged and retorqued.

Picture 1 top of nut
Picture 2 where found
Picture 3 bottom of nut

Probably just a dropped nut from the assembly line. Workers often grab a handful so they don't have to keep going back to the parts bins for more, and every so often they drop one. It's not worth the time at the factory to pick it up.

I was thinking that was a possibility and most probable unless it back off and fell down.

That looks like it fell out of the lower transmission cooler shroud.

It could be one of the nuts that holds that cooler to the frame...see image below. Either take it to the dealer, or pull that shroud off to inspect...use just a drop of locktite (I might go with red, because stuff gets hot down there)...and put it back on.

Attachment 920222

Ok I look into that and follow up.

Not the transmission cooler nuts all present and accounted for. The transmission cooler nuts are darker in color too.

Well that's good. Maybe it was a spare that was just dropped...I don't think there's a very easy path into that cavity from anywhere else...tons of chutes and closeout panels.

Is that steel or aluminum/aluminum alloy? The color and way it's pitted look more like aluminum to me. If it is, that might help narrow down the location.

This is also a pretty unique nut design. I can't find the exact thing anywhere online.
The basic arrangement is called a free spinning washer nut, but that does not account for the three internal slits. I think they may be a self-locking mechanism, but I am not sure.

that looks pretty beat up to be something that was new and dropped. i'm guessing you picked up a hitch hiker