I had the dealer do the tsb probably 6 or 7 months ago (they subcontracted it out to a body shop). Yesterday I noticed it's back. The tailgate is covered with a lot of it. I don't drive off road or anything, what would caused it to come back? It's to cold for me to be out there trying to remove it I guess I will have to have them do it again.

 

Tailgate, lower quarter panels behind the wheels and rocker panel is the most common place for the "rail dust". IMHO you are seeing brake dust metal particles on your truck.

There are three major causes of paint contamination:

1. Rail dust - produced from the friction of train wheels against railroad tracks. Over 70% of new vehicles are shipped by rail. Rail dust can contaminate a new car's finish before it even reaches the dealership. Anytime a vehicle is parked or travels near a railroad it is subject to rail dust contamination.

2. Brake dust - particles produced from the friction of brake pads rubbing against the rotor. This metal on metal friction disperses tiny particles of bare metal into the air and on the highway where it collects on passing vehicles.

3. Industrial fallout - another word for pollution, industrial fallout is a byproduct of our modern industrial age.


Railways are not the only source of this dust. Just about any process where metal moves against metal will produce fallout. Even your own car's brakes and engine produces fallout. If you park your car anywhere near factories and foundries, manufacturing plants or even a car body shop which uses welders and grinders, you expose your car to a degree of fallout which floats about in the air until it lands on your paintwork. All cars will have some amount of industrial fallout or ferrous metal contamination. The severity depends much on where you drive your car and more importantly, where you park your car.

 

Did you just recently replace your Exhaust? Sometimes, a new Exhaust System will leave deposits in the areas you mentioned, until all the inner metallic residue is burned out..

 

"Rail dust" is unfortunately just a fact of life. It's going to happen just as Silverfish explained and white shows it like no other color.

Also as 1buddyc said, if you have a dual exhaust system straight out the back, you can pick it up from there as well.

My last truck was white with duals straight out the back. I couldn't keep the rust spots ("rail dust") off of the tailgate. It was worse in the winter for some reason. Maybe because of faster rising exhaust gases or could have been from less frequent washing.

That's the main reason I went with a side exit exhaust this time.

 

Stock exhaust. I just cant believe it came back so quickly. Maybe since it's white it needs to be waxed more than normal, any volunteers How harmful is this to the paint?

 

I don't imagine it's good for it but there isn't a whole lot you can do about it. It will imbed in a coat of wax as well.

Just keep a supply of clay bars onhand to hit those areas and rewax after you wash.

My last truck showed it really bad down low along both sides as well. No doubt from the brakes.