Doc's Diesel maintenance kit with filters and other replacement parts

How to Install a Full Maintenance Kit on 2013-2018 Ram 2500/3500 6.7L Cummins

Published on September 24, 2025

Install a Full Maintenance Kit on Your 2013-2018 Ram 2500/3500 6.7L Cummins — DIY Made Simple

What’s up, diesel crew? If you’re running a 2013-2018 Ram 2500 or 3500 with that powerhouse 6.7L Cummins, you know how important it is to keep her running smoothly and strongly. Lucky for you, swapping out your oil, fuel, and air filters doesn’t have to be a headache, especially with our Doc’s Diesel Full Maintenance Kit designed just for your truck. So, oil, fuel filters, air filters, we're going to go through everything.

What You’ll Learn Today:

How to swap out those filters like a pro with our premium kit
Quick tips for draining and refilling your engine oil without a mess

CHECK OUT OUR YOUTUBE FOR MORE TUTORIALS

Step 1: Replace the Air Filter

For the air filter change, you'll need a Phillips head screwdriver or an 8 mm socket. There are just three screws on the filter. You pull them off, open the air box, remove the old filter, and slide in the new one. Clean air means better performance and fuel economy.

Step 2: Swap the Fuel Filter

Now that your air filter's done, it’s time for the fuel filter. So the engine-mounted fuel filter is on the driver side of the engine, and on the top of the cap, there is a little one and one-eighth spot to put your socket. We like to throw this down on there first and then fish our extension down into there. So, before you pull the cap off, there is a little drain to get the fuel out of the fuel filter housing. It's going to be the little yellow cap on the bottom of the fuel filter housing, and just turn it to the left and drain the fuel out. Now going back in with the premium Doc’s Diesel fuel filter. Don't forget to remove your old o-ring and reinstall the supplied o-ring for the cap. Your fuel filter keeps your diesel clean and your engine happy. Locate the fuel filter assembly, carefully relieve any pressure, and swap in the new filter from the kit.

Step 3: Drain That Old Oil

Next, we’re going to get rid of that old oil. First, get your truck up on the lift, and you’re going to pop the oil drain plug to do the oil change. You're just going to need a three-eighth ratchet for this. First, let your engine cool if it’s been running; nobody wants a burned hand. Pop the drain plug and let that old, dirty oil flow out. Grab your gloves and a catch pan to keep things tidy. Remember, proper disposal of used oil is key!

Step 4: Change the Oil Filter

Next up, unscrew the old oil filter. The oil filter on the Cummins trucks is in a little bit of a tricky spot, but luckily, the Ram engineers got us a little window here to access it. You're just going to need yourself a little oil filter wrench and make sure you are unscrewing this with your hand underneath so it doesn't fall and blast oil everywhere. Grab an oil filter cap and screw this guy onto the top. Make sure that the gasket comes off the oil filter, as sometimes this will stick to the housing and you don't notice. Grab your brand-new Docs Diesel premium oil filter and slide it in.

Pro tip: Before you install the new one, rub a little fresh oil on the gasket to help it seal tightly and make removal easier next time. 😉

Step 5: Fill ‘Er Up

Pop that drain plug back in, then refill with fresh engine oil (check your manual for the right specs). You guys don't need to put anything on here to tighten it. The oil is going to expand that rubber, and it's going to make a tight seal. So if you tighten it and then that expands, you're never getting it off. Let's fill it up with some oil, double-check for leaks, and now you have a fresh oil filter installed. We're going to go ahead and fill her up with the sweet Docs Diesel 15w40. This truck takes 12 quarts or three gallons. You can use 5w40 if you're somewhere cold, or use 15w40 if you're somewhere warm. Throw the cap back on and you’re all set.

Step 6: Replace Your Cabin Air Filter

This is going to be the same from 09 to 18 on these Ram 2500 and 3500s. It's going to be right behind your glove box. So to pull this glove box down, you're just going to squeeze in on both sides. Once you get your glove box removed, you're going to see your cabin air filter. All you do is just pinch both sides - this one can be a little harder to reach. Your cabin air filter cap comes off; simply slide out the old cabin air filter and pop in your new one. This is going to be a nice little upgrade for the HVAC system. Snap back into place and reinstall your glove box. And that's that! That's a full, all the essential stuff you guys need to do on your Ram to keep these things running for a couple hundred thousand miles.

Ready to DIY? Grab Your Maintenance Kit Today

Because your Cummins deserves parts that last and perform under pressure. Our kits use only the highest quality components designed to keep your engine humming, mile after mile. No shortcuts, just reliable power for your diesel beast. Don’t wait for that next service to roll around. Grab your 2013-2018 6.7L Cummins Full Maintenance Kit right here and keep your Ram running like a champ: Shop the Kit, and keep your truck tough and your diesel roaring with Doc’s Diesel; your partner in heavy-duty performance replacement parts.

MAINTENACE KIT ESSENTIALS

Good stuff, on time, awesome price! These guys are on top of things when it comes to service. Almost feel like they communicate with my truck. I’m about to order the front hubs, it’s that time. Overall 5 stars.

Carlos Nunez