We just received an proposal from a non-Tesla shop (okay, Electrified Garage) about a potential catastrophic failure of the drive unit and an offer to replace it for about $4k. I don't see a lot of talk on any forum about this being a problem. My wife's 2012 S has 149,000 miles and has had a whine from the rear end since about 35,000 miles in 2016 or so, when Tesla was saying that this wasn't a problem and wouldn't cover it under warranty. EG is selling a less expensive fix than Tesla for a problem that we don't know we have and that may be caused by a bad bearing in the motor. Before committing to this, I'd like to hear from other owners. Thanks for your input.
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Early Tesla S drive unit failure
- Thread starter pastperfect44
- Start date
ajbessinger
Owner of QC Charge #2 (Portland OR)
This is a VERY common problem area for these cars. Early Large Drive Units (LDU for short) were very prone to noise issues due to the use of steel rotor bearings, which would end up becoming the path of least resistance for energy built up in the rotor to dissipate to the case (e.g., literal arcing through the bearings, causing pitting in the balls and races).
Tesla fixed this on the later iterations of the LDU, but ended up switching to an inferior rotor coolant seal design, which tends to wear out much more quickly than the original triple lip seal (that said, even the triple lip seals wear out eventually). When the rotor coolant seal starts to go, it leaks coolant inside of the motor, and can cause seriously catastrophic damage to the drive unit (loss of HV isolation, corrosion, damage to inverter electronics, etc.), not to mention, it could also leave you stranded.
I'm not familiar with E.G.'s procedures on inspecting their donor drive units, but make sure that the replacement drive unit at a bare minimum has been inspected for signs of coolant intrusion, or better yet, been modified with a rotor cooling delete of some sort (much like the newest U-rev LDUs from Tesla).
Tesla fixed this on the later iterations of the LDU, but ended up switching to an inferior rotor coolant seal design, which tends to wear out much more quickly than the original triple lip seal (that said, even the triple lip seals wear out eventually). When the rotor coolant seal starts to go, it leaks coolant inside of the motor, and can cause seriously catastrophic damage to the drive unit (loss of HV isolation, corrosion, damage to inverter electronics, etc.), not to mention, it could also leave you stranded.
I'm not familiar with E.G.'s procedures on inspecting their donor drive units, but make sure that the replacement drive unit at a bare minimum has been inspected for signs of coolant intrusion, or better yet, been modified with a rotor cooling delete of some sort (much like the newest U-rev LDUs from Tesla).
Unfortunately we see this all the time now. So many failed due to the rear seal leaking. We have a kit to prevent this.
We have a kit to prevent this problem. Been running it in our cars for a bit with no issues.
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