The latest drive unit explanation

[kennybobby]

Totally New Monster Shaft

Increased the motor shaft length and diameter. Massive splines to mesh with gearbox. Would love to see how the coolant circulates. Upper photo of the newer motor rotor (from the video linked by JRP3) to compare with the earlier version in the lower photo.

The diameter of the newer motor shaft looks to be as large as the outer race of the bearing used in the older version--that thang is huge.

 

[notAmeenPerson]

Increased the motor shaft length and diameter. Massive splines to mesh with gearbox. Would love to see how the coolant circulates. Photos to compare newer with earlier versions.

Interesting. When did that information come out? I'm surprised to see pictures of drive unit production. The last time I saw them was in the national geographic documentary a while back.

 

[mikeash]

Increased the motor shaft length and diameter. Massive splines to mesh with gearbox. Would love to see how the coolant circulates. Photos to compare newer with earlier versions.

Please excuse my complete and utter ignorance: which photo is the newer one?

Edit: thanks for the edit saying which is which!

 

[notAmeenPerson]

Please excuse my complete and utter ignorance: which photo is the newer one?

My money would be the bottom being new. The top looks similar to what I've seen in the past in published videos.

Edit: Lost figurative money. Shows I'm not a gambler. I just thought the bottom red ones looked cooler and more colorful.

 

[supratachophobia]

Elon also stated that they have changed their internal goal from a 200,000 mile drive unit to a million mile drive unit.

Next question... do any of you care that your drive units are internally rated by Tesla for only 200,000 miles? What about all of the talk about electric motors being far less complicated than an ICE engine, less moving parts, more reliable, etc., yet the DUs in circulation today will only last 200,000 miles? Seems like a low number to me. Anything to be concerned about?

You mean 20k miles.... That's about when most experience problems. Their internal goal needs to hit 200k before it can hit a million.

- - - Updated - - -

I care. I plan to keep the car for 8-10 years, that should put me close to 200k miles when I'm done with my Model S (we do about 20k miles a year, and have been doing more with the Tesla for whatever reason).

If that means the cost to fix/swap the DU after the warranty expires will be half the cost of the car, then that'll tank my resale value.

Now if my DU goes bad between now and then, and they swap it even once in the next 7.5 years, the 200k rating doesn't bother me one bit.

ETA: I agree with the poster above, if the MTBF is rated at 200k miles, that means it could last a lot longer than that.

ETA2: I'm assuming catastrophic failure, not service at 200k miles. If it's just a "tune-up" at 200k, then I don't care.

If the MTBF is 200k, that's means there are others that will fail before then as well....

 

[JRP3]

Increased the motor shaft length and diameter. Massive splines to mesh with gearbox. Would love to see how the coolant circulates. Upper photo of the newer motor (from the video linked by JRP3) to compare with the earlier version in the lower photo.

Please excuse my complete and utter ignorance: which photo is the newer one?

Upper photo.

 

[kennybobby]

Thread about the drivetrain explanation from a previous conference call (cable vibration, $3 cable tie, and differential, 50¢ shim):

Drive unit problems explanation by Elon

 

[brucet999]

If Tesla is like SpaceX, it is pretty much a bunch of twenty something engineers making it up as they go along. …Sometimes stuff blows up.

I'd be leery about doing a launch, then.

 

[supratachophobia]

The solace I am taking away from the whole exercise is that this is Tesla's first drive unit, they will learn and it will be better moving forward. I'll keep this in mind all the way to the service center next week as I drop my wife's car off for a DU swap.

It's actually, like, their 17th drive unit if you consider all the revisions....

 

[Sunlight]

It does non-plus me that it is taking Tesla so long to resolve this issue. If some folks are having 5 DUs then the mileage on some must be minimal?

Surely one of the major attractions of EVs is the simplicity and long-lasting-ness of an electric motor. Maybe it is FAR more difficult than we realize......

BUT the good outlook is that for 8 years owners will be getting free DUs which (other than the inconvenience) will eventually result in the 'revised/latest/perfect' version being fitted - which will then last for a million miles from replacement (which should take some cars to 1 200 000 miles!)

By that logic surely a time must come (soon..?) when new cars' DUs are faultless and replacement DUs are the new version so the issue should evaporate suddenly overnight and the Tesla bad taste will fade away over a few months (years?)

I suspect this is the logic Tesla itself is following/hoping for....

 

[loco]

I recall Elon saying..." We are very happy with the quality of the new drive units - over the last several months quality is excellent"... not a direct quote but that was the message. You got the spline grease info above. Thanks JRP3.

Yeah, I heard that too and thought it's because it takes a few months for them to start failing

 

[mhpr262]

I wonder what all these replacements and refurbishments are costing the company ... I suspect the numbers aren't pretty ...

I only hope that the people who have had DU trouble are mostly already gathered in the various Tesla forums, and all others have no issues and we don't hear from them.

 

[lolachampcar]

Just keep in mind that the DU and the Battery are the two most important and novel elements of the car's design. The battery costs significantly more so I am glad they put more engineering resources into the battery. Degradation has been nothing short of unbelievable. The few failures there have been seem to revolve around the contractor.

Tesla will get their drive unit sorted and will likely get to their 1M mile MTBF. Until then, it is the lessor of the two big ticket items and is easily swapped. Heck, the Service Centers have been "working on their time" to the point that they likely doing them like a Le Mans Audi engine swap

It is inconvenient for all of us with DU swaps but, if I had to pick one nagging issue associated with a ground up new design of a completely new transportation concept, this is not a bad one and it could have been a lot worse.

 

[brianman]

Just keep in mind that the DU and the Battery are the two most important and novel elements of the car's design. The battery costs significantly more so I am glad they put more engineering resources into the battery. Degradation has been nothing short of unbelievable. The few failures there have been seem to revolve around the contractor.

Tesla will get their drive unit sorted and will likely get to their 1M mile MTBF. Until then, it is the lessor of the two big ticket items and is easily swapped. Heck, the Service Centers have been "working on their time" to the point that they likely doing them like a Le Mans Audi engine swap

It is inconvenient for all of us with DU swaps but, if I had to pick one nagging issue associated with a ground up new design of a completely new transportation concept, this is not a bad one and it could have been a lot worse.

Also, the motor necessarily has moving parts which (IMO) by definition means it is more susceptible to lower MTBF than battery.

 

[brantse]

Increased the motor shaft length and diameter. Massive splines to mesh with gearbox. Would love to see how the coolant circulates. Upper photo of the newer motor rotor (from the video linked by JRP3) to compare with the earlier version in the lower photo.

The diameter of the newer motor shaft looks to be as large as the outer race of the bearing used in the older version--that thang is huge.

That motor shaft is impressively large. Unless there's something internal that we're not aware of, the only reason that I can think is to create an extremely stiff shaft in an attempt to avoid harmonic resonance. Considering that it doesn't have the advantage of multiple speed ratios, there's a huge operating speed band which could present some challenges ensuring that no critical speeds are encountered.

 

[Max*]

If the MTBF is 200k, that's means there are others that will fail before then as well....

There are already a ton that failed before hand, so that would skew the results for the "good" ones to last much longer than 200k miles

 

[kennybobby]

There are already a ton that failed before hand, so that would skew the results for the "good" ones to last much longer than 200k miles

Wishful thinking--the design goal was 200k, but the actual MTBF is determined by the field data...

 

[islandbayy]

Just keep in mind that the DU and the Battery are the two most important and novel elements of the car's design. The battery costs significantly more so I am glad they put more engineering resources into the battery. Degradation has been nothing short of unbelievable. The few failures there have been seem to revolve around the contractor.

Tesla will get their drive unit sorted and will likely get to their 1M mile MTBF. Until then, it is the lessor of the two big ticket items and is easily swapped. Heck, the Service Centers have been "working on their time" to the point that they likely doing them like a Le Mans Audi engine swap

It is inconvenient for all of us with DU swaps but, if I had to pick one nagging issue associated with a ground up new design of a completely new transportation concept, this is not a bad one and it could have been a lot worse.

I need to disagree with you. DU's and Batteries should be the absolute most reliable part of the car. Most already know, I'm getting DU #4 tomorrow. First one was the Clunk, that got loud enough to echo between houses on my street. Second one was milling noise that was loud enough that Neighbors could hear it IN their homes as I drove by, and #3, has intermittent power loss at random times. #3 is a Revision P drive unit, and has been the most dangerous. In a Median making left turn, press the accelerator to complete my turn in between streches of cars coming from opposite direction, Wham, no power, DNRP turns Red, that oh schnit moment when that Semi is approaching while speeding.... Then all of a sudden powers back and it lurches forward. This has happened a number of times. It is scary, especially with children in the car. Granted, safest car in the world, but I'd rather not test that.

It's gone beyond nagging issue, and has dipped into the realm of just being dangerous. With each new Drive unit, they have had shorter and shorter life span. In fact, in hindsight, I had thought these power-loss problems with #3 were potholes and other bumps in the road, as at first, it happened so quick, it felt more like a bump. But now looking back, and how each time the power loss gets worse.... It was happening almost immediately since #3 install.
I will have had 4 drive units in my car in less then a year as of tomorrow. This is ridiculous. Battery.... I had the battery failure at 34,000. It was the contactor. I had the 60kWh "A" Pack. They were at least able to remedy that issue, and I rarely see people with contactor failures any longer, however, the drive unit issue seems to be getting worse, and number of people having repeat failures is increasing in my observation, not decreasing.

 

[supratachophobia]

I wonder what all these replacements and refurbishments are costing the company ... I suspect the numbers aren't pretty ...

I only hope that the people who have had DU trouble are mostly already gathered in the various Tesla forums, and all others have no issues and we don't hear from them.

The shipping alone is the scary part. I think it's something like 800 bucks to ship a drive unit and close to 2k for a battery. It's not something you drop off at your local UPS store.

 

[Vitold]

#3 is a Revision P drive unit, and has been the most dangerous. In a Median making left turn, press the accelerator to complete my turn in between streches of cars coming from opposite direction, Wham, no power, DNRP turns Red, that oh schnit moment when that Semi is approaching while speeding.... Then all of a sudden powers back and it lurches forward. This has happened a number of times. It is scary, especially with children in the car. Granted, safest car in the world, but I'd rather not test that.

It's obvious from your description that symptom you experience (with revision P as you mention) is not by design but rather due to faulty component or botched replacement job. Perhaps your tesla shop needs more training.