NHTSA's August 5 investigation dataset records defect petition DP26001 as closed on August 4. The agency opened the petition review on March 6 after receiving a January 9 request to investigate alleged spline failures between the transmission and rear-wheel-drive power takeoff unit in certain 2021–2023 Acura TLX and 2022–2023 Acura MDX vehicles.
The closure date is confirmed, but the disposition is not. NHTSA's flat file still carries the opening summary, no recall campaign is linked, and a closing resume was not publicly retrievable when this report was published.
What the petition alleged
The opening summary says spline failure can interrupt power transfer to the rear axle, leaving the vehicle operating with front-wheel drive only. The petitioner alleged that the resulting loss of all-wheel-drive capability reduces directional control and cited 48 complaints submitted to the agency.
NHTSA opened DP26001 to evaluate whether to grant or deny the petition. Opening the review did not establish that a safety defect existed, and the newly recorded closure date does not reveal the agency's decision by itself.
Why the missing decision matters
A closing resume would provide the language needed to distinguish a denied petition from a granted petition, a transition to another investigation or another administrative disposition. None of those outcomes should be inferred from the word “closed.”
There is no confirmed new remedy, recall, customer instruction or dealer action in the cited dataset. Retailers should avoid telling owners that NHTSA either validated or rejected the allegations until the agency publishes the decision.
What dealerships should do while the outcome is pending
Service teams can document customer symptoms and current vehicle findings without representing DP26001 as a recall. Used-vehicle staff should distinguish an investigation record from an open safety campaign when answering shoppers or evaluating affected model years.
The next meaningful update will be the closing resume or another official NHTSA record stating the disposition. This article will be updated when that document becomes available.
NHTSA's dataset confirms the August 4 closure date but not the disposition. This report does not characterize the petition as granted, denied, substantiated or rejected, and it identifies no new recall or repair instruction.
Cited references
- NHTSA defect-investigation dataset — Federal investigation dataset; updated Aug. 5, 2026; DP26001 closed Aug. 4, 2026
- NHTSA investigation data dictionary — Federal field definitions for opened, closed and recall-campaign data
- NHTSA datasets and APIs — Federal dataset index; investigation files updated Aug. 5, 2026