Nissan Frontier OEM Part Numbers Decoded: How to Read, Search and Verify Them

Somebody searching 850186td2b is not browsing. They have a broken part, they’ve found the number stamped on it, and they want the same thing again for less than a dealer charges. That search is the single highest-intent thing anyone types about a truck — and it works only if you know how to read the number and how to search it.

This is the reference for doing that on a Frontier: the anatomy of a Nissan part number, what the leading digits mean system by system, how supersession works, and the search routine that actually returns listings.

The anatomy of a Nissan part number

Nissan numbers look like this:

17251 - 3JA0A
  │       │
  │       └── design code: which vehicle/variant, and which revision
  └────────── function number: what the part is

Two blocks, normally five digits then five characters, separated by a hyphen.

The first block is the function number. It says what the part does. It is not Frontier-specific — the same five digits mean the same kind of part across Nissan’s whole catalog. 17251 is a fuel filler cap whether it’s on a Frontier, a Versa or an Altima. This is why cross-vehicle interchange works at all.

The second block is the design code. It says which vehicle and which variant that particular part was engineered for, and its last character is normally a revision level. Two numbers identical except for a trailing A versus B are the same part at two points in its life.

The first two digits of the function number place the part in a system family. That’s the part worth memorizing, because it lets you glance at an unfamiliar number and know roughly what you’re holding.

Section families you’ll meet on a Frontier

Treat this as a strong convention rather than a guarantee. It is consistent enough to tell you what system a stray number belongs to, which is usually all you need to start searching — but the only authority on whether a specific number fits your truck is a VIN-based catalog.

Four numbers decoded, from parts you can actually buy

The method is easier to trust when you can check it. Every one of these numbers appears in a real listing for a real Frontier part:

• 17251-3JA0A — leading 17 puts it in the fuel tank and filler group; 17251 is the fuel filler cap. Confirmed by the listing for this replacement gas cap, which cross-references two numbers — 17251-3JA0A and 17251-1VZ0D. Two design codes, one function number: the same cap in two variants.
• 96409BC402 — leading 96 is the mirrors, console, visor and trim group. It’s the sun visor clip retainer — the little hook the visor snaps into that every truck eventually snaps off. Note the listing prints it with no hyphen at all, which is exactly why you search it both ways.
• 999T7-ZV00A — the 999 prefix marks it as a genuine Nissan accessory, not a service part. It’s the Utili-Track bed cleat — a tie-down anchor for the factory bed rail system, exactly the kind of dealer-catalog item that lives in the 999 range.
• 96965-ZP00C — 96 again, trim: the center console cup holder insert for 2005–2019 trucks. The trailing C is a revision level — this is the third iteration of that design code.

And the one that started this page: 85018-6TD2B leads with 85, so it is a rear bumper part — a bracket, retainer or finisher rather than the bumper skin itself, given the 018 position in the family. The design code identifies which truck and which variant, and that is the part to confirm in a VIN catalog before you buy. See the body panels and collision parts reference for what a bumper listing does and doesn’t include.

One more worth knowing: the wiper washer nozzle listed as 28931-3S500 — leading 28 is the wipers, audio and horn group, right where the table above puts it, and this one’s a genuine D22-era (1998–2004) Frontier part rather than a design code shared with something else. Which brings us to the traps.

Where part numbers mislead

RH and LH are different numbers. Left and right versions of the same part are usually adjacent function numbers — 66814 and 66815, 26010 and 26060 — not the same number with a side suffix. Order the wrong one and it will look completely correct in the box and fit nothing.

A number can be a kit or a piece. Brake pad numbers like 41060… are axle-set kits; the same job in the catalog may also list individual shims, clips and hardware under their own numbers. Read what the seller is actually shipping.

Color- and trim-keyed parts share a function number. Mirrors, handles and interior trim come in painted, chrome-cap and textured-black variants, and the difference lives entirely in the design code. Matching the function number alone gets you the right shape in the wrong finish.

Aftermarket listings quote factory numbers as cross-references. That’s helpful — it’s how you find the right shape — but it doesn’t make the part OEM. Read the listing for who made it. For clips, trim and hardware an aftermarket equivalent is usually the sensible buy; for anything structural, electrical or safety-related, see the used, OEM and salvage buyer’s guide for where that line sits.

Supersession quietly changes the answer. When Nissan revises a part, the catalog points the old number at the new one, and the chain can run several steps. If the part failed on your truck because of how it was designed, buy the newest revision, not the number stamped on the broken one.

The search routine that actually works

Part numbers are the best search terms in the entire parts market — they cut through every fitment guess — but only if you search them the way sellers list them. Run these in order:

1. The bare number, no hyphen — 850186td2b. This is how listing titles are most often written and how most people type it.
2. The number with the hyphen — 85018-6TD2B. Different sellers, different results.
3. Function number + vehicle — 85018 Nissan Frontier. This is the search that finds the part when nobody has your exact design code, because it surfaces the same component under sibling and superseded codes.
4. Function number + plain-English name — 85018 rear bumper bracket. Catches sellers who never typed a full number at all.

On eBay Motors all four are worth running, because the used and salvage inventory is listed by thousands of independent sellers with no shared naming discipline. That inconsistency is exactly why a part-number search beats a keyword search there — and it’s why the eBay rails on this page point at the number families rather than at product names.

For consumable service parts where you want a new one rather than a used one, the numbers in the 15…, 16…, 22… and 27… families are the ones on the maintenance schedule and parts checklist. For brakes, 41060 and 44060 pad kits are the starting point — the brake pad types reference covers which compound to put in them.

Verify before you buy: the three-step check

1. VIN, not year. Feed your 17-digit VIN to a catalog and read the numbers Nissan actually built into your truck. Year alone doesn’t know your cab, bed, drivetrain, trim or mid-year running changes — and the Frontier’s generation and fitment boundaries are where most wrong orders happen.
2. Match the function number exactly; treat the design code as negotiable-with-evidence. The first block must match. A different design code may be a documented supersession, a sibling variant, or the wrong part entirely — confirm which before you pay.
3. Confirm the side and finish. RH/LH, painted versus textured, heated versus not. This is where a correct number still lands you a wrong part.

The bottom line

The function number tells you what a part is, the design code tells you which truck it was made for, and the last character tells you which revision. Read those three things and a random string stamped on a broken piece of plastic turns into a search that finds the same part, used, for a fraction of dealer price. Search it four ways, verify against your VIN, and check the side and finish before you pay. Live eBay Motors listings below.