OEM vs. Aftermarket Parts: 3 Key Differences to Help You Decide

In the debate over OEM vs. aftermarket parts, there is a lot of misinformation derailing the conversation. While many customers lean toward OEM parts, this is usually due to confusion surrounding the quality of aftermarket parts. As experts in the industry, we’re here to clear up some false perceptions that may be preventing you from choosing the best part for your clients.

OEM vs. Aftermarket Parts

OEM: True or False?

OEM parts are made by the manufacturer or a plant that the manufacturer owns.

While this is a widely held belief, it is false.


In reality, OEM suppliers outsource the parts that they need with factories that have the capabilities to produce those parts. These suppliers do have strict guidelines for these factories, which must adhere to OEM specs and Quality Control standards. OEM parts maintain the original manufacturer’s design and often come with a warranty—hence why they tend to be pricier.

However, because customers believe that manufacturers make these parts themselves, many mistakenly believe that an OEM part is always better than an aftermarket part.

Aftermarket: True or False?

The aftermarket exists in the automotive arena solely because some OEM parts fail.

This is true!


Aftermarket part creation is a lengthy process that must take several factors into account. Manufacturers must solve these questions before producing aftermarket products:

  • Why is the OEM part failing?
  • How many or what percentage of these parts are failing? 
  • What improvements does the aftermarket part need to incorporate in order to fix the problem?
  • What is the longevity of the part?
  • Can the aftermarket produce the same part with the correct updates and still save the customer money?

The intent is to improve on the OEM part and save the customer any repair costs, one of the main differences between OEM vs. aftermarket parts.

3 Key Differences to Keep in Mind

When considering OEM vs. aftermarket parts, here is a brief guide to the most important distinctions.

#1: Design

OEM parts match the original auto part. High-quality aftermarket parts expand on the original design to correct any failures.

#2: Production Time

Producing aftermarket parts tends to be a lengthier process. For just one part, a manufacturer might need to find several different factories. Some parts require more than one factory since they can have different integrated parts, such as gears, housings, washers, bearings, pins, stamping, and so on.

To find the factories, make the blueprints, order the raw materials for production, make a prototype, test the part, send the part out for inspection and approval, and finally hand it over to production can be a long process.

#3: Tooling Costs

Each individual aftermarket part must be made to certain specifications, therefore, most of the time there are several tooling costs involved compared to OEM production.

Our Aftermarket Parts Catalog

Need high-quality aftermarket parts that stand up to rigorous use? Work with a manufacturer who specializes in transmission rebuilds. You can reach our GFX office in Miami at +1(305) 499-9789. We are available Monday through Friday from 9 AM to 5:30 PM EST.

You can also check out our catalog to find aftermarket transmission parts for your clients’ cars. We offer both used and new parts to fit your clients’ budgets and needs.