German automaker said differential fluid in some AWD models never needed replacement—owner class-actions say otherwise

The plaintiffs contend BMW previously specified differential-fluid service intervals before moving toward lifetime-fluid guidance during the 2010s. They allege the company knew lubricant performance could deteriorate with age and use, potentially contributing to component wear.

The complaint also points to service openings in the differential and BMW maintenance documentation as evidence supporting its allegations. Those claims remain disputed, and have not been established by a court.

BMW’s maintenance guidance has since changed for certain vehicles. Beginning in 2025, the automaker recommends front and rear differential and transfer-case fluid service for all-wheel-drive M vehicles at five years or 50,000 miles (80,000 km). Heckler’s vehicle, however, allegedly failed before reaching either threshold.

The litigation follows a separate proposed class-action filed in December 2025 concerning transfer cases in numerous BMW vehicles from model years 2019 through 2025. Plaintiffs in that case allege a clutch-system defect can interfere with torque distribution between the front and rear axles, producing driveline shudder and potentially leading to failure.

This complaint cites a BMW technical service bulletin involving transfer-case fluid changes and alleges the service does not permanently address the underlying condition.

The Pennsylvania differential action seeks more than US$5 million (CDN$7 million) in damages and other relief. Both lawsuits remain pending, and the plaintiffs have not proven their allegations.

Sign up for our newsletter Blind-Spot Monitor and follow our social channels on X, Tiktok and LinkedIn to stay up to date on the latest automotive news, reviews, car culture, and vehicle shopping advice.