Mazda CX-9 noise under the car during acceleration and deceleration, possible power transfer unit reliability issue on Mazda CX-9

Some Mazda CX-9 owners report experiencing noise during acceleration and deceleration, which may indicate issues with the power transfer unit (PTU). This component has been identified as a common problem, with failures leading to significant concerns such as transmission damage. Additionally, a class action lawsuit was filed against Mazda regarding PTU issues, resulting in a settlement. The design of the PTU, particularly its proximity to the exhaust system, has been noted as a potential cause for overheating, which can deteriorate the gear lubricant and lead to sludge formation. Complaints filed with the National Highway Traffic Safety Administration (NHTSA) reveal a pattern of powertrain issues across various model years, making the powertrain and transfer case among the most frequently reported problems by Mazda CX-9 owners. For those experiencing these symptoms, it is advisable to have the PTU inspected by a qualified mechanic to address any reliability concerns.