Should I have this checked out?

Front or rear ?
Year of truck ?
4x4 or 2wd ?

 

Looks like a big dog pissed on your tire and rim is all...
If there was a problem there would be stuff coming out from all points and the full rim and tire would look the same.

Also there is not much of anything liquid or grease that can come out.

 

Rear drivers side, 4x4. 2012

 

I can see that makes sense

 

A small screwdriver will pop the center cap off .
Shine a flashlight behind the wheel .
Leaking axle seal or leaking brake cylinder comes to mind .
The dog pee is also another good point depending on how long the stain has been there . Check to see if the stain is oil based
Oil sticks around , dog pee goes away when you wash the truck

 

But that is on the back side of the drum and would need to fill the drum to come out the front and you would see the inside of the tire and rim covered in oil or grease and it does not look to be.
Also the fender liner would be covered. Can't really see in the picture but I bet he would see it and smell it.

 

I'm going to take a look

 

I'm going with the dog urine theory.

Brake and diff fluid will have a tough time getting around the drum and weeping through the lug holes.

Plus, let's say that was the case of oil spinning out onto the rims... the pattern would look like spin art. That looks like piss dribbled on the rims... there's even a few spots in the middle of the rim too.

 

No spin art probably urine

 

No spin art probably urine

 

Thanks for the replies to all. No spin art and it doesn't reek like diff fluid

 

Had this and looked at the breaks and rim and all couldnt find a leak. Then one early morning caught my dog "marking his territory"..u can be sure and just wipe it with a paper towel. Isnt gonna smell like grease or oil.

 

you ran over a soda bottle and the stain is some sort of sugar residue happened to me and even found it on top of my roof

 

Bear whizz is my guess.

 

Lick it and if it tastes like piss, you found your problem...LOL! J/K, I'm going with urine too, I've seen that before on my truck.

 

Funny you mention that. I live in an area known for black bear roaming the area.

 

I say "Piss on it!"

Actually, I'd wash it off, and monitor it for a while to make sure nothing comes back.

 

Definitely dog piss. My neighbor's dog does it to my truck almost every morning before i get up and go to work. I've seen him do it. I conveniently put dog turds next to his mail box.

 

Pour some sugar on it. I read about that working online (so it must be true) and gave it a try at the base of a post in our lawn. Some neighbors were letting their dogs piss on the post which left a dead area at the base. To my surprise the sugar seemed to work. It really can't hurt anything to try.