Systems to make ordering and controlling parts inventory are a great boon to fleets, but given the wide variety in parts choices and prices, there’s still one important question a fleet manager needs to answer: “What’s in that box I bought?”

The array can be bewildering and the differences substantial even if they may not be readily apparent, so it’s important fleets understand the differences if they want to choose the best balance of initial price, quality and reliability for their particular applications.

Let’s start with the general categories that denote goodbetter- best quality.

The “best” level is what most classify as OEM parts, that is, parts coming from the original manufacturer of the truck. Designed as an integral element of a larger assembly, those parts will be identical (or occasionally updated) from the When it comes to part s, price isn’t the only variable ones originally installed during the manufacturing process.

For example, gear sets from the company that made a truck’s transmission, or a brake cam from the original supplier of the foundation brake system are considered genuine OEM parts. OEM parts are almost exclusively available through the manufacturer’s truck dealers.

Warranties for OEM parts are usually 1-yr./unlimited mi., but sometimes can extend to the full warranty period of the vehicle.

Branded parts are similar to OEM parts, coming from major component suppliers to the truck manufacturers and representing identical replacements for the parts used on the original new truck. Eaton, Meritor and Bendix, among others, offer OEM replacement parts for their various products under their own brand names. One significant difference is many component suppliers also sell under their brand name replacement parts for assemblies made by others. Branded parts are distributed through truck dealerships, independent parts networks, and the companies’ own dealers. Warranties for branded parts vary, but are usually similar to OEM parts.

Moving to the “better” category are what those in the truck aftermarket call “all-makes” parts. These are generally lower cost than OEM parts and cover more than a single brand of truck or component. They are consolidated from many sources and most often marketed under a single name. The consolidator may be a truck OEM selling under a unique name such as Daimler Trucks’ Alliance brand or independent parts networks such as NAPA. Major component manufacturers such as Meritor also distribute all-makes parts that complement their own, for example, offering brake components for competitive brake assemblies alongside theirs.

All-makes warranties vary widely by supplier and part.

Price Overall

The final “good” category is one where initial price trumps all other considerations. It includes what the aftermarket calls both will-fit and white-box parts.

As the name implies, will-fit parts are manufactured by third parties as replacements for branded or original parts. They are usually limited to high-volume items that can be mass-produced for the lowest cost possible. Since producers don’t have access to the original design documents, they are most often reverse engineered from new samples.

White-box is a relatively new term for parts that come without any brand name. A subcategory of white-box parts are bulk or container-load offerings from offshore sources, which are often the lowest cost parts option. In either case, there is no name or brand attached to the part.

The quality of will-fit and white-box parts can vary greatly, as can functional life. Without attributable brand names, unknowns include manufacturing tolerance variables, testing procedures (if any), material quality and workmanship. Warranties can vary from none to limited replacement of failed parts.

One other option for fleets is remanufactured goods, or remans. These are components that have been disassembled into individual parts, which are then inspected and replaced or renewed when required before being reassembled into specifications that are similar to brand new components.

Remanufacturing suppliers are usually medium to large assembly operations often run in separate plants by the makers of the original components. Performance and life should be equal to new, but prices are up to 60% lower. Warranties usually include parts and labor with national coverage.

Remans should not be confused with rebuilt parts, which are usually single components that have been repaired to replace only the failed parts and generally do not meet original equipment specifications. And salvaged parts are just that, parts removed from scrapped vehicles and sold for reuse as is.

Obviously, price differentiates the various parts categories, but a fleet needs to look beyond initial cost to accurately weigh the total cost of ownership for an individual truck and its intended application.

Top quality is expected from an OEM or branded part, making it the choice for “anyone who is interested in retaining the original performance level and reliability of the vehicle,” says Paul Tuomi, director of parts sales for Daimler Trucks North America (DTNA). “Customers know that if they put [an OEM or branded part] on a vehicle, it meets our rigorous standards for durability, quality, fit. It’s buying peace of mind.”

What might not be so obvious, though, is that the best category also brings consistency in materials, tolerances and other manufacturing variables, according to Terry Livingston, Meritor general manager for the aftermarket in the U.S. and Canada. “They should fit like a hand in a glove,” he says. “They’re not only made specifically for that vehicle, but as a global manufacturer we ensure consistency.”

In comparison, a will-fit part is typically reverse engineered. “There is always a small range of tolerances in manufacturing,” says Brad Bagley, Meritor senior manager of drivetrain products. “If the sample they use [for reverse engineering] is on the high or low side of that and then you add their manufacturing tolerances, you lose that consistency from part to part.” Good Compromise

All-makes parts reduce the initial cost by “defeaturing,” according to Livingston. They can be a good compromise between durability and cost for owners of older trucks, he says.

“At that better level, the feature set may be below a genuine OEM part, but you’re still getting the same warranty and nationwide availability” from DTNA’s Alliance parts group or other major parts suppliers, according to Tuomi. All-makes is not just a product category, it’s also a distribution channel, he adds. All-makes suppliers like Alliance offer just that—parts for all makes, allowing fleets running a variety of trucks to get what they need from a single source.

Will-fit will certainly lower initial price, but the real cost could easily negate that original savings. “They may work at first, but if the maker doesn’t know all the mechanical requirements, you can end up with something that’s cheap at first, but costs more in the long run,” says Livingston.

While will-fit parts carry a manufacturer’s name or brand, white-box parts don’t offer any identification. “They may be good—or not,” says Tuomi. “You don’t know where they came from, so the trade-off for low cost is risk because the manufacturer didn’t even put their name on the box.”

As for remanufactured parts, “they’ve demonstrated their value for many years,” says Tuomi. “It depends on the supplier behind them, b