Just bought a used truck and want to make it last? Don't know the maintenance history? Here's an explicit guide of things to check over.

THIS IS A LARGE LIST. PREPARE YOURSELF!

Edit: Be sure to see u/bammad33's comment for greater elaboration on some points and other suggestions.

I love r/trucks, so I wanted to help some people out if I can. I bought my truck a couple months ago with 100,000 miles on it, and since that time I've been going over the entire truck performing maintenance that I had no idea if it had been done before. I created this list in case it might be helpful to those in a similar situation as me. Some might say I went over kill, but because I bought the truck with 100,000 miles on it, and knew nothing about maintenance history, I did every thing I could think of to make sure it would last a long time. For those more knowledgeable than me, feel free to add your own ideas. (note, this is geared towards gas engines--I don't know anything about diesels!).

If you've never worked on cars before, I'll go ahead and rank the subjective level of difficulty (1-5). You can save a TON of money doing this yourself. Don't be afraid to get in there and give it a go.

Fluids

• Engine Oil/Filter (1)--this is an obvious one, but I know a lot of people who don't know how to change or even check their own oil. Obviously it's easy to just take it to a quick service place, but if you decide to do it yourself, you can purchase better quality oil and filters for the same price, while knowing that the job was done correctly. Look for ads at your local auto parts stores (LAPS) for monthly sales to save some money. If you insist on going to a quick change place, most of them will price match competitors prices. It's pretty easy to find a $19.99 change.

• Rear Differential Fluid (3)--this is one that is usually overlooked for the average truck driver, but doing this can prevent large scale repairs in the future. Although it seemed a daunting task at first, it really is nothing more than removing the faceplate, draining the fluid inside, putting a new gasket on the faceplate, and refilling it with fluid. Prices from fluid range from $7 a quart, to $20 a quart for the "better" fluid. Buy whatever you feel is necessary, but because the rear differential is moving every time your truck is, I wouldn't skimp on this. Also, if you get this done at a quick-lube place, all they do is suck out the old fluid and put new in. They don't replace gaskets, clean off the magnet on the faceplate, or even really get out all the old fluid. But do what you want to.

• Front Differential Fluid (3)--For those of us with four wheel drive, this is another place to look. Although some people say, "I rarely use four wheel drive, the fluid is fine", I've seen some front diffs that are completely rusted out because no one checked the fluid and water got in. On my personal truck, there were only two bolts--a drain plug and and a filler plug. No faceplate or anything to mess around with. A quick and cheap maintenance item that can save you in the long run.

• Brake Fluid (3)--This one is extremely important, because brake fluid is hydroscopic and will absorb water over time. More water in your brake fluid leads to corrosion of your brake system--that's BAD. People change their brake fluid is a couple of different ways. Some just uncap the reservoir near the master cylinder, suck out the old fluid with a turkey baster, and refill with new clean fluid. But this doesn't get rid of air bubbles in the lines, and still leaves contaminated fluid behind. Others use the Two Person Method, some install speed bleeders, and others (like me) use pressure bleeders like Motive's product to make it an easy one man job. There's many other ways as well, YouTube will give you tons of ideas. Regardless of how you do it, this is an important service to have done. Places like Midas and such will do this for around $50. You can weigh price over convenience. And NEVER let brake fluid touch your paint, for the love of god.

• Radiator Coolant (4)--I rate this at a 4 even though it is pretty straight forward, because it takes a greater amount of time, and the process can be a little tricky. YouTube is your friend here. Some people go the life of their car without changing their coolant. To each his own, but as a chemist, fluids definitely break down over time. As your coolant becomes more acidic over time, your engine becomes compromised, and you're putting your water pump in jeopardy. This takes an average of $40-$60 to do, depending on if you do it on your own or let someplace else do it. Another good thing to do is to replace your thermostat during this, since now more than ever will be a convenient time to access it. Regardless, this is an important service to have done. Ever hear of people having water in their oil and vise versa? I wonder why...

• Power Steering Fluid (2)--On my truck (and many others), there is no real drain plug for the power steering fluid. You basically just suck out the fluid with a pump (or turkey baster), and fill it back up with new fluid. Some people like to put a high strength cleaner in after they pull out the old fluid and turn the wheels a couple of times with the car on, so if you think your power steering system is pretty nasty, you might want to look at that. This is a cheap thing to do, because there really isn't a high volume of fluid in there.

• Transmission Flush/Drain & Fill (5)--This is probably the most polarizing item I've listed so far, because lots of people have many opinions on it. If you don't know your way around transmissions, I would recommend going to a dedicated shop for this. On my transmission, because I did not know the maintenance history, I was advised against a flush and instead went with a drain and fill. They just dropped the pan, cleaned out all the gunk on the pan itself, inspected the transmission, and refilled with clean fluid for the amount that was lost. This is also the only time you can truly inspect your transmission. But it is costly if you take it somewhere to have done (around $200 is what I paid).

• Transfer Case Fluid (1)--Another item that is usually overlooked, but it's so simple to do and pretty cheap, so why not prevent anything from failing in the future? Very similar to the front differential, it was two bolts: a drain plug, and a filler plug. Fill the new fluid up until it starts coming out the filler hole. Boom, you're done. Total price around $15.

Electrical

• Spark Plugs (2)--For any Ford Triton V8 drivers, this is an absolute must. If you didn't make sure the spark plugs came loose before you bought it, you better make sure they do now. I say that because your guys' plugs have tendencies to break, and then you're definitely shit out of luck. I know SnapOn makes a dedicated part to removing broken Ford spark plugs. I don't say this to talk shit about Ford trucks, I'm just making sure you're aware of the things you need to check to maximize the life of your vehicle. For everyone else, performing this can only help you. My OEM plugs are the iridium ones, which advertise a life of 100,000 miles. So you do it once, and you don't have to worry for a long time! And you can get better hp, mpg, etc.

• Spark Plug Wires (1)--If you're going to do plugs, might as well spent the extra $30 and buy new wires as well. Over time, the rubber boots as well as the metal connections on the wires can get old, crack, or corrode. Replacing the wires ensures your engine is getting the proper spark it needs to operate. And it's incredibly easy.

• Clean your battery terminals (0.5)--I'm often blown away from the corrosion I see on people's battery terminals, it's just stupid. Wonder why your car isn't staring? Probably because your terminals are entirely sealed off by corrosion. Cleaning your terminals and applying electrical grease afterwards ensures that your batter is able to pump out maximum power, especially in this cold weather that's coming up. Go to your LAPS and buy a terminal cleaning device like this for $2. You won't regret it.

• Check your battery and alternator (0)--Your LAPS will do this for free, and it will save you so much headache in the future. Some of you are probably wondering why I would even mention this, but some people just might not know. If you just bought your used truck, get an idea of how these two important parts are functioning.

Other Items of Importance

• Air Filters (1)--doing this every couple of oil changes will help your engine breathe easier, and keeps nasty shit from getting into your engine. It's a $10 part, super easy to change, and that's about all I have to say about it.

• Cabin Air Filter (2)--For those of us who are blessed to have a cabin air filter (not me), you wouldn't believe the change you will see after doing this. Hell, most people don't even know they have a cabin air filter, and the ones I've pulled out have been absolutely disgusting. While it's important for your truck to breathe better, make sure you're breathing fine too. Problems with allergies? Change your cabin air filter.

• Engine Belts (2)--This is something you can have a mechanic charge you out the ass for, but for those of you whose belts are readily accessible, do it yourself and save a ton of money. I know my Chevy's was incredibly easy. YouTube your specific brand and engine type if you're not sure how. While the serpentine belt is often this obvious belt to change, don't forget the (sometimes) separate air conditioner belt. Like cool air in the summer? Make sure your AC belt isn't hanging on for dear life. I can't stress the importance of changing your serpentine belt. You can literally destroy your whole engine if this thing snaps. Because I had no idea if mine had ever been changed, it was the first thing I did.

• Brake Pads/Rotors (4)--Obviously you can make your own call when this is concerned. My pads were squealing and the rotors were incredibly rusty. The pads I bought were the top of the line at my LAPS, and cost me $44 with a lifetime replacement guarantee. Most people don't replace the rotors, but I figured might as well since I'd be down there anyways. Also, buy a brake hardware kit (caliper sliders, new bolts, brackets, etc.) when you're doing this. It's incredibly cheap, and it makes everything a lot safer. Don't let mechanic shops scare you into paying them to do this, YouTube and other resources have very straight forward step-by-step instructions for your specific truck. It might take a while, but it's worth it when you know your truck will stop on time when you're towing that huge load.

• Throttle Body Cleaning (2)--This is another item that some people swear by, while others couldn't give two shits about. I just know that in my experience, I removed a lot of carbon from my throttle body, and it ran so much better after this was done. Quick-lube places often combine this with a high strength fuel injector cleaning. This isn't some snake oil that you pour into your gas tank, it actually is fed through a vacuum hose straight into the fuel injector. After 100,000 miles or more, you better believe that your throttle body and injectors can get pretty gummed up. If you're interested, check out the SeaFoam motor treatment for a similar process.

If you like doing your own maintenance, there are tons of YouTube channels dedicated to this kind of stuff that are wonderful. Eric The Car Guy has a shit ton of videos about car maintenance, as does 1aauto. If you like listening to podcasts, The Under the Hood Show is a FANTASTIC resource where you can learn about so much regarding vehicles. Your LAPS often have knowledgable people who are willing to help, but they also have people who don't know what they're talking about. Be wary. And online stores like www.jegs.com, www.1aauto.com, www.rockauto.com, and many more offer quality parts at affordable prices. Don't get screwed over at your local auto dealer. Haynes Repair Manuals are another awesome resource for DIY maintenance, as they walk you through everything you could imagine with pictures and explanations. Your manufacturer full service manuals (FSM's) are also available, sometimes free on specific forums.

There are other obvious maintenance things that I didn't really go in to here, like tire rotation and alignment, but I tried to hit the ones that most people just glance over. You love your truck, you probably spent a good deal of money on it, so why not get to know it better while making it live longer? I never subscribe to the idea of "don't fix it if it ain't broke", because I think it's a terrible way to treat your car. But that's my own personal idea of my vehicles.

For those of you who want to correct me, or add more ideas for new owners of used trucks to look over, please add your comments. Thanks for reading, and I hope I can at least help one person out with this. If you have any questions, you can always PM me.