I also found that moment interesting. Great way to change the direction of the conversation.
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100% drive unit failure rate??
- Thread starter yobigd20
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- Driving Dynamics Model S
I also found that moment interesting. Great way to change the direction of the conversation.
Well, to keep with the spirit of this thread, just last week, I had a total loss of propulsion due to the drive unit failure and was left stranded. This happened as I was driving in a rotary with minimal traffic and I was able to bring the car safely to a stop on the side of the road. In a different situation, this could have caused a catastrophic accident. For reference, my 18 months old P85 has a little over 50k km.
jpet
Jan P.
Yes, there were some clunk noises from the drive unit that occurred just at the limit where you go from power output to regen. This was subtle initially but had gotten worse in the last few days.
To make matters worse, I was actually at the service center one week before the incident and they diagnosed that the DU needed to be replaced. They gave me an appointment to do this in December, telling me the replacement was necessary but that I could still drive safely until then and that I may hear more noise but that "nobody had ever been left stranded on the roadside" due to this problem. I should add that I live pretty far from the service center and they told me all this knowingly.
jpet
Jan P.
I asked the question because I was wondering if you had experienced the clunk noise. From other owners that had their drivetrain replaced I learned that the clunk is a red flag noise. I have not had any issues with my car so far but I have experienced the clunk during a test drive in a P85 before ordering my car. So I know what it feels and sounds like.
Yes as you mention, this is not just a noise, there is a specific "feel" to it. Initially one may imagine this is just a noise, a small "click" as you pass the 0 kW line. After some time, it becomes clear this is a mechanical issue (as others mentioned in the thread, a noise that did not exist is obviously due to a change in mechanics) as you start feeling a slight jerk and the transition in power is no longer smooth.
The Tesla powertrain is actually most similar to modern railroad/subway traction motors -- but although those run with huge power density, they do not have super-high speed because of the immense weight of the vehicles. And it's pretty easy to ground them through the *metal wheels*. So the electromagnetic problems are slightly different.
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The clunk is a red flag of impending failure. I believe this is the one we suspected of being due to high axial forces causing excessive wear? I strongly suspect that the so-called "improved throttle response at low speeds" in the new software is partly intended to prevent this wear.
The cicada noise seems to go a lot longer and get quite loud before failure. This is the one suspected of being due to electrical current micropitting the bearings?
The two are almost certainly caused by different failure modes and will require different design changes to fix.
P.S. I do think it's important to note that the drivetrain is probably not actually that expensive, compared to the battery or the aluminum body. If Tesla does end up having to replace 50,000 drivetrains, it won't drive them bankrupt, though it could be a cashflow issue. The important thing is for them to figure out what the problems actually are.
If drivetrain failure is bound to happen at one point or another, with 100.000 cars sold (or close to) and some people reporting multiple swaps (my car had started developing milling sound about a year after the first swap), we`re not talking 50.000 swaps.
Of course, some of those 100K cars are dual drives with fewer problems. But on the other hand, it seems as if one swap won`t cut it.
Assuming a DU replacement equals:
- scrap the old DU
- mount a brand new DU
As reports go, it ain't so. DU gets replaced at almost any customer remark or unusual noise. Even when that noise originates from somewhere outside of and near to DU.
So, there is this heap of DU that may have some problem or not. Tesla engineers open them up, test them to see what is going, repair if anything is to be repaired/replaced and ship them back to service center as an OK DU to replace another DU unit the customer is complaining about.
This process needs some money to run, but that money is FAR lower then simply multiplying total number of DU replaced x price of a DU x cost of replacing a single DU (labor, small material bill).
It may be that DU replacement ends up costing a $2000, 50.000 x 2k = 100M.
New DU should cost above 10k, or at least 5 times as much.
It`s not like this at the moment. I`ve read several comments from people who have clunk and/or milling sound on their DU (first, second or third swap) who now get rejected. No DUs available.
To me it seems quite obvious that all rwd Model S have problems with the DU. Just some more than others. Talking with detailers who`ve done 100+ cars reveal that people who think everything is OK have serious clunk/milling.
What about those who report several swaps in just a year or two? One swap hasn`t solved the problem this far. We don`t even know what solution will make the problems go away?
mknox
Well-Known Member
I took my car in for a very noticeable "clunk" as you pass the 0 kW mark, but Tesla Service said it was "normal" and the car was "operating as designed". There is absolutely no change in low speed (or any speed) throttle response that I am able to discern on my car.
Later the cicada "milling sound" came (and has since gotten louder) and Tesla told me they would replace the DU for that, although they tell me it is just a "cosmetic" problem. I am still waiting, but am willing to wait to see if a more permanent fix becomes available.
OK, lots of problem reports. But without solid data on how many DUs in the field are operating in spec, it's hard to put context on these numbers. I'm on my second DU, which seems to be doing a lot better for a lot longer than my first one. I have a 2013 P85+ built in July, delivered in August, with DU replaced about in June, 2014 due to slightly louder noise during operation. The actual reason that led me into a service visit in June, 2014 was my right front passenger door handle jammed and needed to be fixed. I mentioned the DU noise NOT to request a replacement but because I wanted them to assure me that the louder DU operation was fine -- no one else in my life noticed the increased volume and I wasn't bothered by it, only curious. The SC staff just said, hey, it's out of spec, we're replacing it, end of story.
So 10 months on the first DU, 17 months on the second (which still sounds fine). The replacement DU was remanufactured, not new. Is this a story evidencing DU problems (first one needed to be replaced)? Is it a story evidencing deployment of DUs that are more solid (second one has lasted 17 months now)?
Heck, from these anecdotes, I can't even make a broad-brush assertion about the trend line on DU problems. Up? Down? Sideways?
I don't know how to turn these reports into solid projections of pretty much anything other than... well... the issue is real.
Does anyone have better data?
Alan
So 10 months on the first DU, 17 months on the second (which still sounds fine). The replacement DU was remanufactured, not new. Is this a story evidencing DU problems (first one needed to be replaced)? Is it a story evidencing deployment of DUs that are more solid (second one has lasted 17 months now)?
Heck, from these anecdotes, I can't even make a broad-brush assertion about the trend line on DU problems. Up? Down? Sideways?
I don't know how to turn these reports into solid projections of pretty much anything other than... well... the issue is real.
Does anyone have better data?
Alan
Vger
Active Member
Wow! There seems to be a big difference in policy/practice between Toronto and Vancouver. I just got my 3rd DU, but like Pollux above, I did not complain and only suggested they check it out. It was making only a faint humming under moderate acceleration. They said it was the "exit bearing" and swapped it. The 2nd DU had about 50,000 kms on it.
Regardless of whether you think it's a solution or not, that is what Tesla is doing about it. And I think to most extents, it's working. How many DU failures have you seen in the 85D now that they are hitting the 20k mark? I haven't read about any on here *yet*. Now the P85D, I dont know. Maybe the shared load helps, but they also have the same rear DU that the P85's have so maybe they are still at risk.
mknox
Well-Known Member
In fairness, and as others have pointed out, I have not followed up nor made an issue of it with my Service Center. I am kinda hoping to hear they have a more permanent fix. My cicada noise is quite loud now... people on the sidewalk will turn around to see what's coming when I drive through my neighborhood, and passengers routinely question me on what the sound is, so I will bring it up again the next time I'm in.
lol i'd drive it to the SC and drop the keys on their desk and demand a loaner until they fix it.
mknox
Well-Known Member
Yeah, that's why I wanted to point out that it's on me right now. It is noisy, but they tell me (and I have no reason to doubt) that it is only cosmetic and I would rather have it dealt with when a) they have a more permanent fix and b) when I have the car in for other stuff. The Service Center I go to is really busy, they have always been great and I think they would appreciate it if I bring the car in once for a few issues rather than more often for "one at a time" things. I think I'm coming up on another "Annual" soon, so I can see to it then.
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