2013 Tesla Model S: Drive Unit IV: The Milling

July 08, 2014

Just a few days after his epic, cross-country Supercharger-fueled road trip in our 2013 Tesla Model S, Dan Edmunds, director of vehicle testing, sent me the following text:

"It should go in for a post-trip check-up tomorrow, after I wash it. We started to hear a noise in the last 500 miles. And those new tires should be rotated too."

Dan and Kurt are preparing a full update on their trip for publication in a few days. They made it there in record time, breaking Tesla's own cross-country run by several hours. We let them sleep for a while when they got back but they are now working on photos and such.

Dan later told me about an error message he saw on the car's touchscreen: "Bluetooth not functioning correctly, needs service."

We were going to begin the process of selling the car, so it was important to have these things sorted out before listing it. I sent an email to my manager, letting her know this would take up most of my day and quipped, "It'll probably need a new touchscreen and drive unit."

Turns out, I wasn't too far off.

Dan had used the old steering-wheel-button reset trick to clear the Bluetooth error message. Our service advisor, Omar, watched as I paired my phone to the car. The error message didn't reappear. Don't you hate when that happens? Still, Omar said he'd have a technician look into it.

Next, I took a ride with the technician so I could point out the strange noise. I was worried that the car would have stage fright and not make the noise, but my concern was unwarranted. We only drove for a block and a half before the technician recognized the sound. "This noise is known internally as the 'milling sound,'" the technician said.

"What's the common fix for this?" I asked.

It'll probably need a new drive unit, he told me.

The next item on our list was a tire rotation. Tesla normally charges about $60 for this, but Omar said he'd have it taken care of at no charge. He also noticed that our Model S was due for a firmware update and would save us the trouble of updating it ourselves.

Finally, Omar noticed that we hadn't performed the annual service on our Model S. The service includes the following items: annual inspection, replacement parts (includes brake pads if needed and windshield wipers, but excludes tires), system monitoring, hardware upgrades and remote diagnostics. Omar also mentioned that it would include a tire alignment, new cabin filter and a filter for the AC compressor — all this for a cool $600.

We decided to pass on the annual service. The alignment had already been performed when we installed the new tires. System monitoring? We were just there in May when Tesla took care of a laundry list of items. Plus, they were already installing the firmware upgrade as part of the "Courtesy Inspection." Hardware upgrade? Any critical part should be (and was) covered under warranty. More on that later. So the only thing we were missing out on was the AC filters and the wiper blades, not worth $600.

Around midday, I received a call from Omar with an update on the repairs. "The technician sent a recording of the milling sound to our engineers and they gave us the OK to replace the drive unit." It was a unique way of diagnosing the issue.

All the work was set to be finished by the end of the day, but there was an issue with the new drive unit. It had a broken logic connector. This meant that Tesla would need yet another drive unit, which it got from another one of its shops across town. But that meant I wouldn't have the car back that day. Plus, the techs spotted a few other items that needed repairs. Here's how it broke down:

Noise or Vibration While Driving:

The technician found the milling sound coming from inside the drive unit. The solution was to install a new one. When the replacement unit came in, the logic connector was split. Another had to be ordered.

Pay Type: Warranty

Coolant System- Check and Fill:

We didn't ask for this one, so I'm guessing it was part of the process to install the drive unit. The technician performed an air purge in the cooling system.

Pay Type: Warranty

Ride Height Sensor:

The ride height sensor on the right rear of the car needed replacement. They installed the new part and said the car should be a bit quieter. I hadn't noticed, but I'm glad they caught it.

Pay Type: Warranty

Bluetooth Error:

Tesla ran a diagnostic on the system and paired an Apple and an Android phone. Everything checked out. Dan's hard reset must have taken care of this bug.

Pay Type: Goodwill

Tire Rotation:

This was included in the courtesy inspection. We even got a free alignment as a bonus. An alignment is required every time the drive unit is replaced, since the techs have to take off the car's rear subframe for the swap.

Pay Type: Goodwill

Firmware Update:

Also part of the courtesy inspection. We are now on Version 5.11 (1.59.56)

Pay Type: Goodwill

Side Motor Mount:

During the installation of the new drive unit, the technician noticed that the side motor mount had a small crack. Tesla installed a new side motor mount.

Pay Type: Warranty

Active Louver:

The active louvers on the Model S regulate airflow to the radiator. Tesla performed a thermal test and found that the center louver was faulty. The techs installed a new center louver.

Pay Type: Warranty

I picked up the car around 3:30 p.m. the following day. Tesla had offered to bring the car to us, but I planned on taking it home that night and the service center was on my way. Omar was still finishing up the paperwork and offered me a Starbucks coffee from next door. One tall Frappuccino later, the Tesla was back on the road, good as new.

Total Cost: $0

Days out of service: 1.5

Parting Thoughts:

When I wrote about the previous drive unit replacement, I posited that Tesla owners wouldn't be scared off by all the repairs, since they were early adopters who were essentially beta-testing the car. I compared the situation to the rash of faulty Xbox 360s years ago, which didn't deter me from the brand. I caught some heat in the comments.

I was called a Tesla apologist and my very title as "consumer advice editor" was called into question. Here's how I see things now:

Some of you have suggested we pursue a buy-back from Tesla, under a state Lemon Law. But there are a number of criteria that must be met for someone to have a valid lemon-law case, such as the repairs occurring within the first 18 months or 18,000 miles, the car being out of service for over 30 days or four or more repairs for the same issue. The California Department of Justice Web site says:

"The 'Lemon Law' presumption is a guide, not an absolute rule. A judge or arbitrator can assume that the manufacturer has had a reasonable number of chances to repair the vehicle if all of the conditions are met. The manufacturer, however, has the right to try to prove that it should have the chance to attempt additional repairs, and the consumer has the right to show that fewer repair attempts are reasonable under the circumstances."

The car has 30,000 miles on it. It hasn't been out of service for 30 days. And to Tesla's credit, they've taken care of every repair and then some. I'm no lawyer, but this doesn't strike me as an open-and-shut lemon law case.

Driving around the past few days with this car has reminded me of how good it is. People often ask me what I think of it, and I tell them this is an awesome car, with a huge caveat: Be prepared for things to go wrong. The Model S is a highly advanced car from a company that is just learning the ups and downs of manufacturing vehicles on a large scale.

I usually recommend that people lease an EV, rather than buy one. EVs are like smartphones: The technology moves so fast that three years from now, something vastly better will be out. Plus, it avoids any resale and long-term maintenance issues. But leasing is not an option for the Model S (unless you own a business), so if you're set on buying one, or already have one and plan on keeping it for a while, I would HIGHLY recommend that you buy the extended service plan for $4,000.

Here's why: Tesla does not have a powertrain warranty like ever other carmaker. The drive units are covered under the new-car limited warranty of four years or 50,000 miles. Only Tesla knows what these drive units cost on a retail level, or the hours of labor you'd need to pay for a repair out of your own pocket.

The battery has an amazing eight year or 125,000-mile warranty. And though we've replaced our battery once, experience has shown that it's the drive unit you should really be worried about.

As for my Xbox analogy: It was a theory. Sometimes theories are right, sometimes they're wrong. But putting it out there generates discussion and everyone is welcome to agree or disagree. I don't think that makes me a Tesla apologist.

I bet many early Tesla owners felt like they were on the ground floor of a car company that defied the odds. Some have had a smooth ride, while others may have had a ton of issues, like us. This happens with any car company. Some will choose to stick with the brand and others will swear it off forever.

I'm not giving Tesla a free pass, here. The company needs to get these quality issues under control, and more importantly, Tesla needs to have a powertrain warranty like everyone else. I will give Tesla credit for taking care of every repair in a fast and efficient manner. Many non-Tesla dealerships aren't as willing to take on warranty work and be as proactive in fixing things we didn't go in for.

How you view Tesla and the Model S in the future will all depend on your level of investment in the brand. If you're a true believer, these repair setbacks won't alter your course. But if you're someone who wanted a stylish EV to replace a luxury sedan, this may be more maintenance than you care to deal with. Both are valid conclusions in my mind. But if Tesla someday wants to win over the mainstream with an "affordable" EV, these cars must have a bulletproof reputation.

Feel free to agree or disagree with me in the comments.

Ronald Montoya, Consumer Advice Editor @ 30,160 miles