Editor’s note: We published a follow-up article April 23, 2021, detailing what we learned when we brought our F-150 to two independent mechanics and a local Ford dealer for assessments of its underbody rust.
One of the advantages of the 2021 Ford F-150’s aluminum body is that it won’t rust over time like a traditional steel body can. The pickup truck’s frame and many underbody components, however, are made of steel, and while it’s not unusual to see rust develop over years of ownership — particularly in Northern states that use road salt in the winter — some 2021 F-150 owners have reported significant amounts of rust on the underbodies of trucks that are, at most, just a few months old. Cars.com’s 2021 F-150 Limited, purchased in mid-January 2021 as part of our annual Best Of awards program, is just such an example.
The rust issue was first reported by the Detroit Free Press (subscription required) in a story that detailed F-150s with rusty rear axles, rear differential housings and suspension components, among other parts.
The Free Press story prompted us to give our truck’s underside a closer inspection, and it revealed rust issues similar to those reported by owners on forums like f150gen14.com.
Our truck was built in December 2020 at Ford’s Dearborn Truck Plant and currently has around 1,200 miles on its odometer. The heaviest surface rust is on the rear differential housing, the rear driveshaft U-joint, the front driveshaft and the outer ends of the rear axle. Aside from the mere presence of rust on what is essentially a brand-new truck, some of the places where the rust is concentrated are also perplexing; the rust on the rear axle, for instance, is mostly on the upper part of the tubes while the lower portion has less of it.