2020-2023 RAM 1500 EcoDiesel Service Guide (Oil, Differential, Fuel Pump)

First, the RAM 3L V6 EcoDiesel is dead. You can’t buy one anymore after mid-cycle of the 2023 model year. The same year RAM was awarded the most Economical pickup truck award for it’s 30 MPG diesel motor which, paired with a 33 gallon fuel tank gets you close to 1000 miles of range per tank (I average about 750 miles of range or 23 MPGs). It’s disappointing but the future is electric and diesel as a $3000-$5000 extra cost wasn’t purchased enough for RAM to keep this motor in its lineup.

Still, mine is at 30,000 miles and I am very happy with the truck. No complaints at all. I figured after 2 years of doing maintenance, I can finally link to everything you’re going to need to maintain it. I’ll make some notes below on some exceptions you might have depending on your build. Let’s get started.

First, please check your vehicle’s owners manual that came with your truck. Verifty the volumes and specifications and don’t just trust what I wrote below. If your truck asks for a different specification or weight, follow that one and order accordingly.

Finally, I have a YouTube Playlist with a lot of how-to videos on each of these. Give those a watch if you’d like – https://www.youtube.com/playlist?list=PLc-rhUVUGj8tRg0CXQfwbbGw1frSS6wie 

Oil Change:

Every 12 months or 10,000 miles. Change more often in severe situations such as regular towing, off-roading or extra cold climates and finally if you’re using B20 biodiesel. I’d recommend everyone consider doing their oil changes at 6500 miles even if you can go 10K, you probably shouldn’t. Doing it yourself will cost about $75. Cheap insurance to do it every 6 months or 6500 miles.



I’d recommend installing a Valvomax Drain Plug. This makes the oil change so much easier, no mess, no drips and just super easy. I’ve had mine for 2 years and have had no issues. Highly recommended.

Oil changes are super easy once you have the Valvomax installed. After you put in about 7.5 liters, start the motor and run for 60 seconds and then stop it and check the dipstick after 1-2 minutes. I’ve always been able to add a full 8 liters and never gone over the dipstick maximum line but just to be safe, start it first. This pulls oil into the filter housing and other areas and gives you a more accurate reading.

Air Filter:

Very easy to do and should be checked every oil change and performed every 2nd oil change (20K miles)



Cabin Air Filter:

I do this once a year. You can go as long as you want but the sign to change it will be when your cabin air starts to smell dingy or gross. These run so cheap that I just do it every Fall as cheap insurance for not overworking my blower fan as the cabin air filter gets more full of pollen and dirt.

I’m using the BOSCH 6090C which fits just fine. It runs about $15

Diesel Fuel Filter: 

This should be done every 20,000 miles. You’re supposed to drain the water every 10K miles or when the water sensor light comes on your dash. Draining the water is super easy but one word of caution. If you drain your diesel filter or change it or run out of fuel, you need to prime the pump again. You do this by putting your truck in the RUN position (hit start button twice with foot off the brake pedal). Wait 30-60 seconds and let the filter / pump re-prime with diesel fuel before starting it Do this a couple of times or else you’ll be starting your truck dry and will cause issues.

To drain the filter, just turn the little knob on the side of the fuel filter housing (under the driver side door under the truck) and let it drain into a reservoir. To change the diesel fuel filter, drain it first then use a 28MM socket to remove and replace. It’s quite easy and so easy that I’m doing it every 10,000 miles. That’s what is recommended if you run BioDiesel or if you live in a state with low-quality diesel. Check your owner’s manual but it’s so easy to do yourself that the only qualifier is the filters are a little bit pricey.

What you’ll need:

Front Differential:

This fluid does not need to be changed all that often unless you’re towing a lot or driving off road. If you rare are in 4×4 mode, you’ll probably never need to change it. I did at 30,000 miles and the fluid is crystal clear and no sediment. I could have probably gone to 100,000 miles or more before thinking about it. I’d say it’s cheap insurance but this fluid isn’t cheap and, if you have the off-road protection package, it’s hard to get to that front dif without removing a heavy steel pan so changing this is entirely up to you. If I could do it over again, I’d have skipped it. Note, the vehicle must be level for this procedure.

If you have the off road package, it’s a 16mm socket over 4 bolts, you can torque these down to around 34-45 ft pounds with some Loctite 243 attached.



Transfer Case:

Like the front dif, your transfer case isn’t doing much if you’re always in 2WD mode. That transfer case is a big clutch with a Borg-Warner 44 or 48 in it to transfer power on-demand to your front axle if you’re equipped with 4WD Auto mode. If you never use 4WD or 4WD Auto, you’ll likely be like me and change then noticing that the fluid in there is crystal clear and looking great. Your usage should dictate how often you change this but for me, 30,000 miles was way too early. I should have waited to 100K for this. Like the front dif, if you have an off-road protection package installed, it’s not easy to get it as there’s a steel skid plate over it. Note, the vehicle must be level for this procedure.

If you have the off road package, it’s a 16mm socket over 4 bolts, you can torque these down to around 34-45 ft pounds with some Loctite 243 attached. You’ll need a 16mm ratchet / wrench to get one of the bolts off as a socket will not fit over it.



Rear Differential: 

I’m going to change mine every 30-50K miles. Not only was this super foamy and thick fluid when it cam out but it was also pretty slimy…most likely due to the anti-slip additive that Mopar puts in at the factory or some kind of moly grease they use. Given how mine looked, I may even do the next one at 20K miles just for peace of mind to make sure all looks good in there. You’re driving a truck that’s primarily rear-wheel-drive so I’d recommend this be done at 30K no matter what kind of driving you’re doing. It’s not too expensive for what is a very important and daily used component of your truck. Note, the vehicle must be level for this procedure.


  • 8mm Hex Bit
  • Torque wrench (18 ft lb for fill plug and 44 ft ld for drain plug)
  • 14mm Hex Bit (these are all 1/2 inch drive so you’ll need another torque wrench and ratchet to match this)



This is good for 100,000 miles but may need to be topped up occasionally. Mine was at the min line after 30,000 miles so I ordered a gallon of OEM Mopar fluid which is MS-12106. Good to keep on hand and add coolant whenever you see it slightly low.

Miscellaneous parts & tools:

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