Using the Dorman Auto Parts Catalog: A 7-Step Checklist from the Quality Side

Somewhere between "the car started making a noise" and "I already ordered the part," a lot of auto repairs go sideways. I work in quality at Dorman, reviewing new part numbers before they get released, so I end up on the returns side of that gap. Parts come back labeled "defective" that were never defective. They were the wrong variant for the application.

Between Q1 2024 and Q1 2025, I reviewed roughly 100 new part numbers and rejected about 4% of first production samples for hidden differences: connector keying, mounting bracket angles, spline counts. If those differences can catch our inspection team, they can catch a technician working against the clock. Here is the checklist I run through before I sign off on a part.

When to run this checklist

Run it before you order anything that bolts on, plugs in, or carries fluid. I'm going to use four examples that keep coming up on the quality side: CV joint noise, a transmission range sensor, a motor starter, and a pair of suspension bars that people mix up. The same logic applies to most other parts.

1. Name the symptom before you name the part

Write down what the car actually did. Not what you think it needs. That one sentence saves more returns than any other habit.

Example: a clicking sound from the front that gets loud when you accelerate through a turn. That is usually a constant-velocity (CV) joint. The question people ask me is simple: is CV joint noise dangerous? It can be, if the boot tore and the joint has been running without grease. A clicking CV joint can keep working for a little while, but it can also let go when you need it most—like pulling out into traffic. Fix it promptly. Don't wait for the noise to stop on its own.

Another example: the car won't crank in Park but will crank in Neutral. That points to the transmission range sensor or the neutral safety circuit, not the starter. A no-crank condition can involve several different parts, and if you order a motor starter before checking those, you may install a good part into a car that still won't start.

Checkpoint: write one sentence that states when the problem happens and what it sounds like. If the sentence contains a part name, go back and remove it.

2. Search the Dorman auto parts catalog with real vehicle data

The Dorman auto parts catalog is searchable by year, make, model, and engine, but the more specific you are, the better. Use the VIN when you have it. As of January 2025, the VIN lookup on DormanProducts.com handles the trim-level details for you.

That matters more than it sounds. Automakers make running changes during a model year, and a connector can change shape without the rest of the part looking any different. A search that stops at "2022 model" may show two valid options. The VIN narrows it down to the one that belongs on that vehicle.

3. Match the OEM part number, not just the part name

Once you're on the right product family, compare part numbers. The Dorman transmission range sensor is a good example of why.

This sensor bolts to the outside of the transmission and tells the powertrain control module which gear you selected. It also controls the starter interlock on many vehicles—no Park or Neutral signal, no crank. Several transmissions in the same family might use what looks like the same sensor, but the connector can be keyed differently, or one variant includes a separate harness.

A Dorman transmission range sensor listing includes the original equipment (OE) part numbers it replaces. Find the OE number stamped on your old sensor and match it to the listing. If the numbers don't line up, keep looking. "It looks the same" is not a fitment specification.

4. Check the electrical details before buying a motor starter

If you search for a motor starter, you'll often land on the complete starter assembly, with the solenoid mounted on the side. If the problem is actually the solenoid or the relay, you might be looking at the wrong category. That's a terminology check, not a hard one, but it prevents a return.

For the assembly itself, confirm three things before ordering: the number of mounting bolts, the nose length, and the connector style. Two starters for the same engine family can look identical in photos and have different gear offsets. The stamped number on the old starter is your safest reference.

And remember the symptom from Step 1. A single click with no crank often points to the starter or solenoid. Crank in Neutral but no crank in Park points back to the transmission range sensor. If the diagnosis is wrong, no part will fix it.

5. Don't confuse a strut bar with a sway bar

In the suspension and chassis section, two terms get used as if they're interchangeable, and they're not: strut bar vs sway bar.

A strut bar, sometimes called a strut tower brace, connects the tops of the strut towers. Its job is to reduce chassis flex. A sway bar, also called an anti-roll bar, connects the left and right suspension components and twists to control body roll.

They serve different purposes, mount in different places, and are not interchangeable. If you describe the part as "the bar between the wheels," you could get either one. Search by the exact part name and compare the mounting points in the product images before ordering.

6. Test-fit the new part against the old part

This is the step most people skip. Before you install anything, set the new part next to the old one.

For a transmission range sensor, compare the connector keying and the bolt pattern. For a motor starter, compare the nose length and gear position. For a sway bar or strut bar, measure the length and check the end-link hardware. If something is off, stop and re-check the part number before you remove the old part or start the vehicle.

A two-minute dry fit has saved me more times than I can count (note to self: apply this rule to home projects too).

7. Keep the old part until the repair is confirmed

Once the old part is off, put it back in the new part's box. Write the date and the old part number on the box. If the repair doesn't solve the problem, that old part is your reference for diagnosis and warranty. If the repair does solve it, you still have the part number recorded for next time.

I have mixed feelings about warranty returns. On one hand, they are how real defects get found. On the other hand, a big percentage come back as "does not fit" when the returned part was never intended for that application. The part didn't fail. The lookup did.

Common mistakes that make good parts look bad

A few final notes from the quality side:

• Ordering by photo instead of by part number. Photos don't show connector pin count.
• Skipping the VIN because "it's the same model." Running changes are real.
• Throwing away the old part before the job is verified. One loose connector can send you back to ordering a new one.
• Using the wrong term at the parts counter. Strut bar vs sway bar is the clearest example.

We didn't always have a formal process for catching terminology issues on our side, either. The third time a customer returned a starter that was the right part for a different trim, it became clear the catalog notes needed to be clearer. That's why I'm suggesting this checklist: it's rarely one big mistake. It's a few small skips in the five minutes before you click order.