How to Read Mopar Part Numbers and Find the Right Filter for Your RAM Using Your VIN

How to Read Mopar Part Numbers and Find the Right Filter for Your RAM Using Your VIN

If you've ever searched for a Mopar filter and come back with three different part numbers that all claim to be the same thing — 5083285AA, 05083285AA, MO-285 — you're not going crazy. Mopar part numbers follow a specific logic, they get superseded over time, and they use shorthand codes that aren't explained anywhere obvious. This guide breaks down exactly how to read any Mopar filter part number, what the prefix and suffix mean, and how to use your VIN to confirm the right filter for your exact truck before you order.

How Mopar Part Numbers Are Structured

Every genuine mopar OEM part number follows one of two formats depending on its age and category:

Legacy format (older parts): A numeric string with a two-letter suffix — example: 5083285AA

  • The numbers identify the part within Stellantis's internal catalog
  • The letters at the end (AA, AB, AC) indicate the revision level — AA is original spec, AB is the first revision, AC is the second, and so on
  • A leading zero (05083285AA) is simply a catalog formatting prefix — 5083285AA and 05083285AA are identical parts

Modern format (newer parts): An 8-digit number with a two-letter suffix — example: 68157291AA, 68436631AA

  • The 68 prefix identifies these as Stellantis-era parts (post-2009 Chrysler bankruptcy and reorganization)
  • The remaining digits are the catalog identifier
  • The AA/AB suffix again indicates revision level

This is why you'll see 5083285AA and 05083285AA listed as the same filter on different websites — they are. The leading zero is a database artifact, not a different part.

What the Revision Suffix Means (AA vs AB vs AC)

When Mopar revises a part — updated media, improved seal material, refined dimensions — the suffix increments. AA becomes AB, AB becomes AC. The newer suffix is always the correct current part to buy. The older suffix is superseded.

For your filters:

  • 68157291AA — currently AA, no revision. This is the current production NanoNet fuel filter. If you see 68157291AB listed somewhere in the future, that will be the updated spec.
  • 68436631AA — currently AA, introduced with the 2019 platform update
  • 5083285AA — currently AA, unchanged since introduction. The longest-running unchanged filter in the Cummins lineup

If you ever see a part listed with a higher suffix than what's shown here, the higher suffix is newer and preferred.

The Shorthand Codes: MO-285, MO-291, MO-631

Mopar uses shorthand service codes on some filter packaging and in dealer systems. Here's the full translation:

  • MO-285 = 5083285AA (Cummins oil filter, 1989-2024)
  • MO-291 = 68157291AA (engine-mounted NanoNet fuel filter, 2010-2024)
  • MO-631 = 68436631AA (chassis-mounted water separator, 2019-2024)
  • MO-867 = 68197867AB (chassis-mounted water separator, 2013-2018)

When a dealer invoice, forum post, or workshop manual references MO-285 or MO-291, they're talking about the same filters you find on americanoemparts.com under their full part numbers. Same filter, different notation.

How to Use Your VIN to Confirm the Right Filter

Your VIN is a 17-character string found on your door jamb sticker, dashboard, and registration. For filter fitment, two characters matter most:

The 10th character — model year:

  • J = 2018
  • K = 2019
  • L = 2020
  • M = 2021
  • N = 2022
  • P = 2023
  • R = 2024

If your 10th character is J or earlier — you have a 2013-2018 generation truck. Your chassis filter is 68197867AB (MO-867). Get the Mopar Fuel Fier Set 68197867AB + 68157291AA for 2013-2018 RAM at $44.99.

If your 10th character is K or later — you have a 2019+ generation truck. Your chassis filter is 68436631AA (MO-631). Get the Mopar Fuel Filter Kit 68157291AA + 68436631AA for 2019-2024 RAM 2500-5500 at $54.99.

The 8th character — engine code:

  • 6 = 6.7L Cummins turbo diesel

If your 8th character is 6, you have the 6.7L Cummins and all filters in this guide apply. 

The Oil Filter Is the Easy One

No VIN check needed for the oil filter. The mopar 5083285AA (MO-285) fits every Cummins-powered RAM from 1989 to 2024 — 5.9L and 6.7L, every cab style, every transmission. If your truck has a Cummins diesel, this is your oil filter. Full stop.

The standalone Mopar Oil Filter 5083285AA for 1989-2024 RAM 2500/3500 5.9L & 6.7L Cummins at $24.99 is always the right choice regardless of year.

Complete Service Kits by Generation

Once you've confirmed your generation from the VIN, ordering is simple:

2019-2024 RAM 2500-5500 6.7L Cummins — complete annual service: Mopar Fuel & Oil Filter Kit 68157291AA + 68436631AA + 5083285AA — $62.99

2013-2018 RAM 2500-5500 6.7L Cummins — complete annual service: Mopar Oil & Fuel Filter Kit 5083285AA + 68197867AB + 68157291AA — $62.99

Why This Matters for Online Ordering

The biggest source of wrong-part orders online is owners guessing their fitment instead of checking their VIN. A 68436631AA ordered for a 2017 truck won't fit — different threads, different fittings, different mounting bracket. A return, a reorder, and a week of waiting for parts that should have arrived right the first time.

Two minutes with your VIN eliminates that entirely. Check the 10th character, confirm your generation, and order the right kit with confidence. Genuine american mopar OEM filters, correct fitment confirmed, delivered fast — that's the whole formula.

 

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