— The National Highway Traffic Safety Administration won't investigate Acura TLX and Acura MDX all-wheel-drive vehicles following a petition to investigate the vehicles.
The petition claims 2021-2023 Acura TLX and 2022-2023 Acura MDX vehicles allegedly switch to front-wheel-drive while driving.
The problem occurs when splines fail between the front-wheel-drive transaxle and the rear-wheel-drive power take off unit, causing a loss of rear axle drive power.
The safety defect petition alleges drivers can be faced with stability problems, but NHTSA says the vehicles were designed primarily as front-wheel-drive vehicles.
The all-wheel-drive system works more like a performance enhancement feature, according to NHTSA. And even if the splines fail the FWD systems are not affected.
According to safety regulators:
"In addition, the Vehicle Stability Assist (VSA) remains functional, ensuring directional stability through traditional engine and brake-based traction control. Although the condition raised by the Petitioner may degrade the vehicle’s performance characteristics, there is insufficient information to indicate a potential unreasonable safety risk."
NHTSA determined the failure does cause a loss of torque to the rear wheels, but there is no loss of motive power and no stability issues. More than 60 complaints were analyzed and no safety problems were reported from the loss of all-wheel-drive.
In some cases drivers were unaware the problem occurred until the vehicles were serviced and technicians discovered AWD was lost.
According to the government, a defect investigation is not warranted based on the evidence.