Prpbably a stupid question, but I have to find out!!!

I rotated the wheels on my truck today, and noticed a grease (clear) on the back side of my Aluminum wheels where they would bolt to the rotors. Not a grease that would indicate a leak or something ,but a greas that was deliberatly applied to the wheel surface that would bolt to the rotor face. What is this???
Have never seen this done before. Is it to help with a rusting problem??

Dont laugh too lowd!!!

Gooser

 

I would bet it is an anti-sieze compound. There have been a couple of posts here and at FTW about aluminum wheels "sticking" to the rotors.

 

a lot of tire shops will spray WD-40 or similar on the wheel studs before remounting the wheels... helps to prevent X-threading and stud breakage due to rust etc..