I realize I haven't been a member here very long, but I have been on other forums for years. I have been doing this job a long, long time and have alot of experience, both in the army as a Mechanic and in the civilian sector as well. I hope this post contributes to the boards, and maybe saves a few of my fellow enthusiasts some preventable headaches...and maybe even some hard-to-come-by cash.
Until 2008, one of My biggest issues with Dodge trucks was the lack of "sealed" rear wheel wells in the Ram. Road salt/slush sits in the lips inside the fenders and rusts the truck from the inside out, I have seen quite a few, even a few 2007's (they didn't put fender liners in the rear fenders till 2008) that have only been in the salt a few years, and have holes, not spots, HOLES over the rear wheel arches. The addition of fender liners addresses this to a point, but there are really only a few ways to keep your truck from being eaten by rust caused by road salt:
1. Keep salt AWAY as much as possible. This means avoid carrying it in your bed as weight too. It is not corrosive until it comes in contact with water, so if a salt bag gets a hole in it and then gets covered with snow, you are carrying a leaking bag of salt water in your truck bed.
2. If you drive on salted roads, when you park your truck, park it outside or in a non-heated, non insulated garage...yes, in the cold. Water activates salt, and the slush thats on the roads ends up on your truck. Parking outside, that slush freezes, effectively stopping corrosion. If you park a snowy/salty truck in a heated garage, well...you get the idea. The slush melts and you end up with salt water eating away at your truck...but at least it isnt cold when you get in it to go to work in the morning. LOL.
3. Wash your truck as often as possible. In winter I use a touchless car wash with an under-body sprayer. I drive over jets of pressurized hot water and it blasts all the crap out from under the truck. I do this once a week. That's $40 a month. If $40 a month is gonna break your bank, you got bigger issues than rust on your truck...like maybe where your next tank of gas will come from LOL (no offense to anyone, just saying). You don't have to do it that often, I am just anal, but I would say no less than once a month at a BARE minimum. It doesn't matter what the weather is, wash the thing. I have come out of the car wash right back onto a wet/salty road, but I got 2 weeks worth of salt off the truck, now I drive for 2 more. If you drive in winter in the north (especially the northeast), your truck will not stay clean longer than a day, so do not even worry about it being clean, the purpose is to rinse off the salt. When it is dirty/salty, be sure not to touch ANY part of it except the door handles. Touching dirty paint, or sliding objects such as cardboard boxes across your hood WILL scratch your paint. Also avoid rubbing/brushing against it with your body.
4. Get a good detailing in right before winter sets in. About the 1st week of October, I will get one final 18 hour detail in. Every INCH of the truck that's exposed (minus the underside, but including rocker panels) gets pressure washed/clayed/polished/glazed/waxed/sealed. I use mostly meguiar's products, which do the job just fine and are readily available at walmart or autozone. I buy in bulk from a supplier because I am a detailer when I am not a soldier
. My way of making extra $$$ on the side.
5. During the summer, get a good undercoating, preferably when the truck is new. You can either DIY this (messy, but i find it fun) or you can have it done by a pro. Good, Professional jobs last 5+ years, and run on the order of $500-1500 dollars depending on vehicle size/age, etc... It can be DIY'ed for about $75, but it will need to be redone, or at least touched up, every year. If your truck isnt new, don't sweat it. Undercoating can still be applied even if rust has already taken hold. The shop will use a rust-reformer/inhibitor, which stops rust dead in its tracks. Reformer's use chemical reactions to create a strong metal surface again.
6. PROMPTLY repair ANY nicks/dings/dents or scrapes, ESPECIALLY those on the lower half and forward facing surfaces of the truck. Dont feel like shelling out money all the time for road rash on the hood or rocker panels? Simple solution, touch-up paint. Sure, it looks like hell, but rust looks worse. If you don't cover exposed metal with some kind of paint or clearcoat FAST, rust will occur in a matter of weeks, and in as little as one winter, you can be looking at HOLES in the side of your truck. Chrome rusts faster than painted metal. If rust on your chrome becomes a problem, hot water with dawn dish soap and some fine mesh steel wool will fix you right up. Follow that with a nice chrome polish and a wax and you are all set.
7. Remove lay-in bedliners. Go spray/roll in or nothing at all. Those plastic pan liners rub the paint in the bed, salt water from the road spray gets in between the liner and the bed, and before you know it, you have a rusty truck bed.
8. MUD FLAPS/bug guards. Cant stress this one enough, mudflaps and bug guards (hood shields) might singlehandedly save your paint...plus on most trucks, especially the Ram 2500/3500 4x4's, they just look kickass.
9. Your interior needs protection too, get some good floor pan type mats to cover your carpet. If your carpet gets covered with salty snow/slush, it stays wet all winter. whats under your carpet? That's right, its metal...almost bare metal at that. There is very little paint under your carpet, and the metal, especially at welded seams is extremely vulnerable to corrosion, so kick your feet off (NOT on the side of the truck) before you get in and have a good set of floor mats that will collect the crud, so you can dump it back on the ground where it belongs.
10. Last but not least, STAY OUT OF THE PUDDLES OF "WATER" ON THE ROAD IN WINTER. You aren't rinsing off your truck by ripping through the puddle on the side of the road, you are, in fact, driving through salt water. Minimize the impact of salt on your truck, stay clear of the puddles. If the entire road is wet, its ok, keep driving, just remember to hit the car wash on payday.
Its very rare that you find a vehicle in the northeast US, that is more than 4 years old that isn't starting to fall apart. Its not because they are crappy vehicles...its because they weren't taken care of properly. Rest assured if you don't take precautions to protect your investment, rust WILL destroy it.