https://parts.lakelandtoyota.com/p/__/Adjust-rod-LINK-SUB---ASSEMBLY--HEIGH/17364854/48906WAA03.htmlShould be ride height sensor rod

Yup. Go to hardware store and buy a locking nut for itGot the part in, but it seems like they've changed the design for the newer adjusting rod. It no longer uses a push clip top side, but instead a threaded part that requires a nut. Some diagrams will have include this part some won't. The nut doesn't come with the rod.
https://autoparts.toyota.com/products/product/self-locking-hex-nut-90118wa889