One of the most common issues with the large rear drive units in Tesla Model S and Model X is coolant leaking into the motor. This problem stems from the original design of the cooling system, where over time, coolant can seep past internal seals and enter the motor housing. Once inside, it can lead to bearing failure, electrical shorts, and ultimately, complete motor failure if not addressed in time.

When we service these motors, we perform a full teardown and inspection. We replace the bearings, flush and change the gear oil, and most importantly, install a coolant delete cover. This modification prevents coolant from entering the motor again, effectively eliminating the root cause of the failure.