Transit bus parts on a white background and the KIRKS logo in the bottom left

What You Need to Know When Buying Transit Bus Parts

Millions of people rely on transit buses for getting to work and to medical appointments. With commuter buses logging thousands of miles every year, buying the highest quality transit bus parts at competitive prices should be a top priority for fleet managers.

In this article, we’ll highlight everything you need to know about buying transit bus parts, including when to purchase OEM (original equipment manufacturer) replacements, when to buy remanufactured parts, and which brands on the market provide the most value.

OEM Replacements Versus Remanufactured Products

Both remanufactured products and OEM replacements provide great benefits, but there are some important differences between the two.

OEM Replacements

OEM parts come directly from the original dealer or manufacturer. When you replace a broken transit alternator with an OEM alternator, you know that the part will fit perfectly and work smoothly in connection with the engine and battery. The downside of OEM transit bus parts is that they are more expensive than remanufactured parts, receiving the part may take some time, and on certain occasions, may not offer the same quality standards as the original part.

Remanufactured Parts

Remanufactured or “reman” parts are cores that have been repaired and restored to perform like a new part. A reman part is inspected and evaluated to determine what component(s) need to be replaced. Replacements may be new or repaired components that meet the factory standards of the manufacturer.

A remanufactured component is often less expensive than an OEM replacement and sometimes necessary if that component has been discontinued by the manufacturer. Most remanufacturers, like KIRKS, will offer an OEM-quality guarantee and warranty, but be sure to check before you purchase any remanufactured product.

Available Brands

Once you’ve decided whether you need a reman or OEM replacement part, the next step is knowing which brands you can trust. As a leading supplier of transit fleet equipment, we’ve searched for the most reliable and valuable brands on the market, some of which include Roadwarrior™, AMETEK®, Delco Remy, Bosch, Transit Cooling Solutions, and E3 Spark Plugs. Below, we’ve listed some of the products we carry from each brand.

Roadwarrior™ DPFs

Roadwarrior™ is a reliable aftermarket manufacturer specializing in Diesel Particulate Filters (DPF). Their DPFs offer superior filtering abilities that capture and store exhaust particulates (soot) to reduce emissions from transit buses and diesel-powered trucks.

At KIRKS, we carry the following Roadwarrior™ DPFs:

  • C0252-SA: This is a direct-fit replacement for Cummins® DPFs: 5295605 and 5579356.
  • C0213-SA: A direct-fit replacement modular DPF for Cummins DPF: 4965244, 4352923, 4352920, and 2880169.

Roadwarrior™ DOC

Diesel Oxidation Catalysts (DOC) are critical after-treatment systems that can extend the life of heavy-duty engines. DOCs are fitted to the exhaust systems of diesel-powered vehicles to break down any unburnt particles into non-toxic gasses. As an aftermarket manufacturer, Roadwarrior™ offers a wide range of OEM direct-fit replacement DOCs for brands like PACCAR, Detroit Diesel, Caterpillar, Cummins®, and Volvo/Mack®. All of Roadwarrior’s™ DOCs are manufactured in the United States, constructed with 490 stainless steel, and come with no core charges.


ROTRON® pumps made by Ametek® have a “seal-less” design that provides leak-proof reliability and requires little to no maintenance service. These top-quality pumps resist fog, hot water, vibration, and other environmental stress that may quickly damage other pumps. KIRKS carries the following ROTRON® pumps:

  • 150178-21: Designed to last up to 60,000 hours, this 47 Frame brushless pump is constructed from cast bronze and has a flow rate of 18 GPM. Replacement for Gillig part 21-57567-000.
  • 151001-99P: This seal-less water circulation pump can last up to 40,000 hours, is quiet, and is perfect for demanding applications. Replacement for Gillig part 21-73653-002.

E3 Spark Plugs

Established as a national leader in spark plug technology, E3 spark plugs offer cutting-edge ignition technology that enhances natural gas (CNG) engine performance, reduces emissions, and improves the operation of an engine’s combustion chamber.

Remanufactured Cummins® Compressor 4938827

KIRKS carries a high-quality remanufactured Cummins® compressor (#4938827) that works on all Cummins®-powered transit buses.

Get Reliable Transit Bus Parts from KIRKS

Do you need help selecting the right equipment for your fleet? Get in touch with our team at KIRKs. Founded in 1946, we specialize in selling OEM replacements and certified reman products. Every remanufactured product you receive is certified by our KIRKS Approved Equal™ stamp, which guarantees that the product meets or exceeds OEM specifications. 

Visit us online to view our complete list of transit bus parts or contact us today to reach out to one of our experts.