Tesla Shows Off Model 3 Drive Gears After Million-Mile Testing

OCT 16 2018 BY MARK KANE 36

Those motors will outlast the car.

Tesla reiterated yesterday that the Model 3 drive systems are designed for over 1 million miles (1.6 million km) and that it’s validated, which means tested in under simulated real-world conditions.

As proof, the company shows off how the gears appear after testing. Elon Musk, in a separate tweet, adds that both motor and gearbox are in solid condition after 1 million miles.

“Designed for ultra high endurance.”

What does that really means to us? Well, there is no need to worry much about drive systems in used cars and your drive system will last for the entire life of the car and probably even longer (for example, in other after-life projects like conversions). That’s the beauty of electric machines and simple single-speed gearboxes.

Tesla Model 3 gears after over 1 million miles – still in good condition

Categories: Tesla


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36 Comments on "Tesla Shows Off Model 3 Drive Gears After Million-Mile Testing"

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I’ve seen similarly pristine pics of ICE teardowns after a million miles of lab testing. That said, EV drivetrains should easily outlast the rest of the car. It’s the little things (or collisions) that usually get you.

An ICE transmission’s hard pack would perform similarly. It’s the clutches, actuators and sensors that do in automatic transmissions. Let’s hope EVs stick with single speed gearboxes.

I would bet money on a two speed and maybe later a 3 speed gearbox may come to some EV models.

I really think that the tesla approach on the model 3 D will get rid of the need for multi speed mechanical gear boxes for $40K and more expensive vehicles. It does complicate the electronics a bit though. Really active range of cars are 0-100 mph (0-200 kph on the autobahn maybe). 2 different gearings for the motors can easily hit this range. On less expensive cars, sure maybe you have a 2 or 3 speed and cheaper motors and electronics, but the units on the bolt and leaf don’t seem too expensive or hard to make.

Gears become relevant for sports cars as well. They improve efficiency, allowing for smaller and lighter batteries for the same range, while improving performance with smaller and lighter motors

No need from 0 to felonious speed with just 1 gear. Electric motors are efficient over much of their operational range.

In the never ending hunt for efficiency multi speed motors are an inevitability, at least on larger and more complex vehicles.

Completely agree and some of those “little things” can cost a ton of money. If you want a shock go price power seat motor kits. On my otherwise bullet proof Camry one of those went bad and the tab was $1500+ for the part. Hopefully Tesla will see so many model 3s that parts are readily available on the aftermarket / used market because it as a *lot* of little motors in it. Power trains in BEVs or for that matter most ICE are the least of my durability concerns these days.

Check for compatible parts. ASMO (a Denso company) may for example deliver motors to several seat manufacturers, and several brands use the same parts. The price of the parts on the other hand may vary a lot from brand to brand.
It’s just a tiny motor with a plastic gear box, but of course some brands price the parts like they were ment for aerospace use.
The same goes to fan motors, or power window motors… there are compatible motors, and some manufacturers also use the same parts.

I assume this was gearbox was tested with ludicrous with P100DL like power/torque on every run?


It’s the M3 not the Model S

Another Euro point of view

This is great and I hope it will soon be obvious to all that EVs will most likely bring real added value for the consumers as regards long term reliability and running costs as compared to ICE.

who cares about constant speed mileage. How many full throttle accelerations can it do?

“Real world conditions” imply real world load profiles, not constant speed.

Tesla boasts with the most abrupt power delivery while others tame the power onset down. So I want to know how often you can floor the throttle from a standstill.
Real world load profiles are surely rather lame cruising and soft accelerations.

about 99 ..lol

Super, now put it in a damn truck already.

The Model Y is next. After that is the pickup truck. You have to wait several years.

I believe it’s Semi, Roadster, then Y. Semi and Roadster are low volume builds at first. I do hope this changes as I like to breathe and these pre-clean air act lungs need a break.

It is going into the semi and this kind of reliability is exactly what a semi needs.

Insedeevs do better journalism, please.
The very first question you should have answered for yourself (and use your readers), is standard of quality pertaining to gearboxes. Is visual scrutiny useful at all in ascertaining quality? If so is this particular picture enough to make any statements about quality?

Please add such info to your article. Thank you.

Visual scrutiny certainly is useful in ascertaining whether or not there is visible wear. That should be self-evident.

With gearing yes, it is possible to visually judge a components wear and quality. In fact if you step back a century or two you can learn a lot from a little engineers blue.

I imagine they may do further x-ray testing for cracks too, but those pictures tell enough. Don’t forget, this isn’t a newly developed technology, it’s a known quantity.

I don’t know if this really shows anything. They are constantly engaged gears. Assuming good manufacturing tolerances and lubricate these things should last for a very long time. And I assume they are also doing real analysis would include metallurgical analysis to look for micro fractures – not just pictures of a gear.

This is either Musk waffling and being amazed by the most simple things again, or he’s trying to build hype over nothing in the hope less knowledgeable people think that Tesla has achieved something.

Remember when he announced the Roadster would make 10,000NM at the wheels, something any high performance ICE matches with ease? This is the same sort of thing.

This is impressive, because it shows what humans are capable of, but it is also meaningless and proves nothing.

Given the frequency of drive unit replacement in the early years of the Model S, apparently most often for a “milling noise” which apparently was a problem with the reduction gearset, I’d say visual proof that the TM3 reduction gearset can stand up to a million miles of driving with no visible signs of wear is very far indeed from “meaningless and proves nothing.”

However, I would be more impressed if Tesla had done this to several units and had shown us the results on each and every unit. Showing us just one single sample smacks of cherry-picking the best of the lot.

Ah, so I was aware of the drive unit replacements but wasn’t aware of the milling noises. Were they replaced out of fear of failure or out of courtesy to the owners? It’s strange to have a component wearing away like that in this day and age, maybe the tolerances were a little bit too tight, not allowing for lubrication?

I agree it would be nice to see some more examples, It’d be nice to see some x-ray images and a bearing breakdown too, but I doubt they’d show that even if there’s nothing to hide.

See my comment above re: bearings. It is likely root of the Model S drive unit problems were gearset bearing problems, not gear tooth problems. (Though a bad bearing can create vibration and/or throw a gear slightly out of alignment and create a gear tooth problem, too.) One of the few problems with the early Chevy Volt drive train was a motor bearing ball-cage materials problem, which would fall apart and made a nasty noise.

And even if part of the quality-concern issue is gear tooth quality after 1 million miles, the comment that those photos may be “meaningless and prove nothing” is valid. With precision high speed/high load gears, the difference between a gear tooth meeting “spec” and and a “worn” gear tooth that can create noise and vibration is frequently at the microscopic level. Small pits, cracks, or scratches only “visible” with magnification, dyes, or other more advanced detection schemes.

“This is impressive, because it shows what humans are capable of, but it is also meaningless and proves nothing.”

The same thing can be said about your statement BTW.

There was an approach wholeheartedly embraced by the auto industry in planned obsolescence. Tesla takes a different approach trying to design a car that will last 20 years+ with no major component failure, unlike legacy automakers who want you ditch that old car for a newer model. If you are adamant to hold onto it, as I am. It’s going to cost you unless you take good care of your vehicle, which most people don’t. Eventually it becomes not worth it to fix, lots of things to go wrong, and you junk it.
The main reason their resale value is so high. They last a long time.

I can believe that Tesla wants their vehicles to last a long time, but thus far their reliability history has not supported that. High resale value has been, in my opinion, more about performance, technology, and novelty or “cool factor” than about reliability. While I’m glad Tesla is continuing to make strides in making their cars more reliable, they still have a ways to go.

With proper lubrication and alignment, the gear teeth never wear out because they never actually contact each other. A micron-thick -film of oil absorbs the tooth-to-tooth pressure.

Before trumpeting the great condition of this gear box, tear apart the bearings. Let’s see the condition of the bearing races and balls or rollers. That’s where the long-term life is really determined, as rolling contact fatigue is typically a far greater issue than gear tooth fatigue. Any pits? Scratches? Bearings are what will typically fail first in a fixed gear box like this, not the gear teeth. The key metric in machine design life is the bearing service life and MTBF. (Mean Time Between Failure).


I have to hand it to Tesla for including an external replaceable oil filter on the Model 3 drive units and providing for gear oil replacement. Clean oil is key to keeping the machinery happy for a long life. This “sealed for life” concept that many manufacturers use (like GM for the Bolt EV’s drive unit) seems like a bad idea.

Sealed for life can be more dependable than maintenance (introduction of contaminants) or breathable designs. Sealed antimony batteries last longer than lead-acid with caps. Sealed steering components last longer than zerk-fitted ones.

Field lubricant replacement is hardly as pristine as clean-room assembly.

After 1M miles the interior would be trashed anyway.

There was never doubt that those gears and motor will easily last that long.

The rest of the car won’t. Things such as suspension, steering, aux parts will wear out. But that is well within expectation at 1 million miles.

That’s great but I believe the weak link in the chain could be the 20700 battery after thousands of supercharging and full discharge cycles. (abusive)