Gotta 2009, stock X, plain ol' wheels with TSP. Noticed this after vacationing through some interesting terrain in what passes for mile-marked highways in the forests in New Mexico. I thought my get home, Missouri back gravel roads were rough.

All of the valve stems I've ever seen are just rubber poking out of the rim. This looks like some kind of metal valve stem protector. In the picture, there is a little line running along the length. The other valve stems are similar in construction without the split, so I assume it is abnormal. Honestly, how many times have I checked the air without noticing this? So it's gotta be new.

The tire isn't leaking air. So is it a problem?

 

It is a nut that secures the valve and sensor to the rim when the pressure is low.

It is a problem. Those crappy aluminum nuts corrode and split like that. I've replaced three of mine and have two more to do. Check your other 4 wheels.

You can get replacement valve stem kits at a tire shop or amazon. about $5.
But then you have to dismount, install, remount, and balance the tire.

Or you can upgrade to 5 new sensors with the rubber stems. The rubber-stemmed sensors are a different frequency than the gray-metal stemmed sensors. Some folks say the JK recognizes them (eventually) others say you need to get flashed.

Beware, there are now three different sensors out there for JKs, you do not want the sensors made for the 2013s

 

This is what you have:
Schrader 433Hz. TPMS SB-20066


This is the newer 315 Hz model SB-33000 (but not the very newest that the 2013s have)


This is the service pack:
Schrader 20013 TPMS Service Pack fits Chrysler Dodge Jeep (1-pack) : Amazon.com : Automotive


BTW, you can't interchange the rubber stem onto the older 433Hz sensor. It won't fit. The old stems slide into the sensor but the rubber ones are held by a screw.

 

I've broke 3 valve stems from rock crawling, 1 made the tire go flat. The 1st one the tire shop said it couldn't be repaired and cost $90 to replace. The 2nd one (when the tire when flat) I had the local shop replace it with a regular (non tpms) one. After the 3rd one broke I had the shop replace all of them with non tpms rubber ones.
What a craaapppy design for an off-road vehicle!

 

wow! thanks for all the information jiblet. $5 part, $90 labor to replace, $?? to flash the cpu. sounds like a soup sandwich, but it's gotta be done.

thanks again for the help guys!

 

You're welcome. Like I said, I had 3 replaced. I procrastinated doing the other two over the cold months but I am going to try replacing the cracked nut without dismounting the tire.

I'll soak it in pb blaster or wd40 and if I can get the old one off cleanly (or break it off then wire-brush clean the stem).
hopefully the tire pressure will hold it in place.
Looks like I now have a project for Saturday morning!
I have nothing to lose!