2014 Tesla Model S power train problems

“Motor suddenly failed after a required update while driving, nearly causing a crash with multiple commercial vehicles and pedestrians, leaving brake lights dangerously always on and alarm sounding, killed 12v as well.”

“**Incident / Defect Description for NHTSA Safety Complaint** **Vehicle Information** - Make: Tesla - Model: Model S - Year: 2014 - VIN: [XXX] - Approximate Mileage: 148,129 miles - Date of Discovery / Failure: 04/23/2026 **Description of the Defect** This vehicle is equipped with Tesla’s Large Drive Unit (LDU / rear drive unit), which was used in the majority of 2012–early 2020 Model S vehicles (RWD and Performance models). The LDU design routes coolant through the hollow rotor shaft. Over time, the rotor seal fails and allows ethylene glycol coolant to leak internally into the motor and inverter. Evidence of this failure is easily visible by removing the rear speed sensor, where blue coolant, corrosion, and debris are present. This is a well-documented design flaw affecting thousands of vehicles. **Consequences of the Defect** Coolant intrusion causes: • Corrosion and rust in the stator windings • Washing out of bearing grease • High-voltage isolation faults • Inverter damage • Complete drive unit failure **Safety Risks** This defect presents an unreasonable risk to motor vehicle safety because: • Drive unit failure can occur suddenly and without warning while…”

“Coolant ingress found on second Model S large drive unit in rear. After this leak destroyed my first vehicle, second was checked as a precaution and was found to have coolant leaking into drive unit as well.”

“The rotor seal on the Large Drive Units on Tesla Model S and X fail, causing coolant to leak into the drive unit, flooding it and damaging the inverter. This leads to a replacement cost from Tesla for approximately $7 - $8,000. As this is a design failure this should be a recall and Tesla should at least repair all units prior to their failure or replace them with an updated motor.”

“My 2014 P85D model S electric rear motor failed. I heard a loud noise coming from it so I took it in to Tesla and they agreed the motor was failing and needed to be replaced, Cost $6,582.04. If I had driven the car and the motor seized up it while on the highway it would have been catastrophic. I would have lost control as the motor froze the rear wheel. Tesla knows of this problem, has replaced many of them, unfortunately post warranty. They know the seals leak and coolant leaks into the motor and causes the motor to fail. They have made a number of design changes including the latest where they eliminate a cooling branch going through the motor. Prior to this change none of the fixes have eliminated the problem.”

“Loud whining noise coming from the rear of the vehicle. Tesla says it needs a new rear drive unit. The noise has been going on for some time and gradually gotten worse.”