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Drive Unit Replacement Poll
- Thread starter nleggatt
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- Driving Dynamics Model S
I doubt it. After I had my first replaced, I babied the accelerator. Still developed again.
dirkhh
Middle-aged Member
Doubt it. I have a 60 and the problem showed up after a 1500 mile road trip during which I was mostly busy not to run out of range (b/c the weather and wind were pushing my Wh/mile way up)... So very gentle driving on the freeway, 99% on cruise control.
I may have just had this happen to me! I am on my way home from TMC COnnect and I heard a mild CLUNK every time I lightly pressed the accelerator or let up on it. Leaving Monterey it seemed a bit louder. By Barstow it was significantly louder. After Kingman I called Tesla and detoured to Phoenix to go to the service center. I didn't make it! Car quit about 10 miles away and had to be flatbedded into the SC. Will know more later today. YUCK!!!
Interesting. I've had some clunk as far back as I recall. Seems to happen when going from regen to +power but I don't think it happens the other direction. It's mild and you can't really hear it unless your trying to pay attention to it. This doesn't annoy me at all. I never mentioned it to SC. Not like the "always whirring" noises that just had to get fixed. Anywho I just had my drive unit swapped last week for the whirring noise but the clunk never changed at all after the new drive unit was in. Whirring gone but clunk stayed the same. I always thought either it was normal or had absolutely nothing to do with the drive unit/motor/inverter at all. Your one of the only ppl I've heard of the car "quitting" on you so I can't wait to hear more details when you find out.
@Chipper - Keep us posted as I am also interested in your case. You have a late production car and likely have one of the last Bs (or perhaps a rev. C pack)? I wonder what it is that causes Tesla's specifically to be prone to the "clunk." I suppose this one may not be tied to the battery pack, but instead the drivetrain?
Call me a skeptic on this whole thing. Tesla's replace vs repair approach means that a drive unit replacement is the standard action for any number of potential issues, so to lump all the different possible failure modes into one category is flawed analysis. Second, I would think Tesla is aggressive about rotating drive units back to the mother ship to see how they are holding up.
Finally, if you look at the numbers Tesla reports in their financial reporting (page 11), back in Q1 of 2013, Tesla reported warranty costs of $3,107,000 for a population of 7,550 Model Ses delivered to date for an average warranty cost-per-car of $411. This last Q1, Tesla reported warranty costs of $9,300,000 for a population of 31,584 Model Ses for an average cost-per-car of $294.
Since I have not seen any upwelling of complaints about service that would indicate Tesla is getting stingy with warranty repair work, what this says to me is that Tesla is getting better at building defect-free cars (yay) and there would not appear to be any pervasive issue with an apparently big ticket item like the drive unit.
Finally, if you look at the numbers Tesla reports in their financial reporting (page 11), back in Q1 of 2013, Tesla reported warranty costs of $3,107,000 for a population of 7,550 Model Ses delivered to date for an average warranty cost-per-car of $411. This last Q1, Tesla reported warranty costs of $9,300,000 for a population of 31,584 Model Ses for an average cost-per-car of $294.
Since I have not seen any upwelling of complaints about service that would indicate Tesla is getting stingy with warranty repair work, what this says to me is that Tesla is getting better at building defect-free cars (yay) and there would not appear to be any pervasive issue with an apparently big ticket item like the drive unit.
InTheShadows
Active Member
I Agree. The car was designed correctly so that it is very easy to replace different parts on the car. The drive unit being one of them. It's much easier to just replace the unit than to mess around with trying to figure out what's going on with it then rebuild it. Those mechanical fix it steps have been left in the ICEage.
Our car had the unit replaced for a clunking that we noticed in parking lots. Along with the drive unit the motor mounts were replaced. That was 8000 miles ago. Since then we have been very pleased with our new unit.
Chippers case sounds very unique to me. When we first had our car diagnosed for the clunking we drove it for another 1500 miles before it was replaced and we put 1000 miles on it before we were able to get an appointment scheduled to get it diagnosed. We have a P and I was in no way babying it while it was clunking.
Anyone know what happens with the drive units?
I was just thinking that it makes perfect sense to replace the entire drive unit if the unit is returned to the factory, repaired and the released back into the wild. In other words, that they replace defective drive units with refurbished drive units that have been repaired (and updated?). The reworked drive units would be more prone to repeat failure, given that there is a greater than zero percent chance of incorrect diagnosis of the root cause of a fault. This would account for there being a significant amount of people who replace their drive unit multiple times.
Is there an accessible serial number on each drive unit, that makes it easy to identify if drive units are being replaced with new drive units or reworked drive units?
I was just thinking that it makes perfect sense to replace the entire drive unit if the unit is returned to the factory, repaired and the released back into the wild. In other words, that they replace defective drive units with refurbished drive units that have been repaired (and updated?). The reworked drive units would be more prone to repeat failure, given that there is a greater than zero percent chance of incorrect diagnosis of the root cause of a fault. This would account for there being a significant amount of people who replace their drive unit multiple times.
Is there an accessible serial number on each drive unit, that makes it easy to identify if drive units are being replaced with new drive units or reworked drive units?
I believe most of them go back to the factory for analysis and repair.
Not sure if I agree with you here. Assuming they understand the root cause and have developed the appropriate fix, I am not sure this would be the case. As one data point, I had the "drone" at ~10K miles and got remanufactured drive unit which has been happily propelling me down the highway for 20K noise-free miles so far.
You are also assuming the repeat failure has the same root cause as the first failure. I think that is one of the reasons they record the motor sound and upload to Fremont, because they can differentiate different failure modes, even if they sound the same to the untrained ear.
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I work with finding and repairing faults on high-tech products. Sometimes you can't be exactly sure what caused the fault. You find yourself unable to reproduce the fault, or you fix whetever is broken, only to have the product fail again down the line. As an example, if a drive shaft snaps - what caused the fault? Imperfections in the shaft? Imperfections in the bearings? Improper alignment of the shaft? Maybe it was something else entirely? Sabotage? Gamma-rays for outer space?
You often find yourself in situations where, after you have done everything you can, you are 90% sure you've sorted out the fault, but you can't be entirely sure because there isn't enough data, and the only way to get enough data is to do destructive testing, which kind of defeats the purpose. If the fault hasn't been corrected, it will in all likelihood happen again once the product starts being used regularly. The question is what you do then; do you toss the whole thing in the garbage and get a new one, or do you assess the risk as acceptable?
For safety-critical things, one might err on the side of caution, but if all it does is cause another trip to the service center, maybe that's acceptable. Now, I don't know what Tesla's pratices are. They might accept a high degree of risk, or they might be very quick to toss suspect HW in the garbage. But regardless, with a repaired unit, the chance of repeat failure will in all likelihood be to some extent greater than with a fresh unit.
I disagree. A remanufactured unit is going to get more individual attention. The build rate is certainly slower and requires inspection of all the components. Brand new drive units have to be manufactured in mass to satisfy Model S production. Remans only need to rebuilt fast enough to supply service demand, which is arguably far less. When remans are inspected, problems that may not have been caught on the line may be revealed and addressed. It just depends on how Tesla does things.
(LMB spouse)
Drive unit replaced once, at around 6,500 miles, for moderate but increasing 60 MPH hum/roar noise. Interestingly, the P85 loaner LMB got had the same noise but much louder. The Watertown (MA) SC manager said he didn't fix it because then it would sell and he would have even fewer loaner cars. This was before the 90-day-loaner-retention policy.
Anyway, the noise has not returned and the car is up to 19,000 miles. It has developed a moderately annoying whine at low power levels, 5 to 25 kilowatts. This is *not* the whine/squeal under hard acceleration. Instead, the volume is affected by the power level, which unfortunately is in the range of typical driving at moderate to highway speeds.
Drive unit replaced once, at around 6,500 miles, for moderate but increasing 60 MPH hum/roar noise. Interestingly, the P85 loaner LMB got had the same noise but much louder. The Watertown (MA) SC manager said he didn't fix it because then it would sell and he would have even fewer loaner cars. This was before the 90-day-loaner-retention policy.
Anyway, the noise has not returned and the car is up to 19,000 miles. It has developed a moderately annoying whine at low power levels, 5 to 25 kilowatts. This is *not* the whine/squeal under hard acceleration. Instead, the volume is affected by the power level, which unfortunately is in the range of typical driving at moderate to highway speeds.
There are certianly factors working for and against repaired units. One element is also that units that have been broken in. Failure rates follow a so-called bathtub-graph. High at first, then low for a long time, and then it starts rising slowly. With repaired units you are certainly past the initial high failure rate, for all parts not replaced in the repair. Provided a drive unit has been correctly diagnosed, a repaired unit should be as good as, or better than a new unit. I think that's about as much as one can say without more data.
But looking at the results of the poll, it seems that if you suffer a failure of the drive unit, requiring replacement, there's a 17% chance of requiring a third drive unit at a later date. If there had been a 0-option on the poll, we could have compared that with the percentage of people having replaced a drive unit, and seen whether this probability was higher or lower than 17%, but we can't do that. :/
OK...here's the deal. It started as a small clunk/clank when ever I would feather the accelerator. It felt like an old car I used to have that had a bad u-joint in the rear. It was just a little bit of play. I took it to the service center for a final check before driving out to TMC Connect and I was told it was NOT normal and they would have to keep the car for a day or two OR I could just drive it like it is and come back after my trip to have it "tightened up". Assured that there would be no further development I chose the latter. 4,800 miles later the barely perceptible clunk was now a clank and obviously getting worse. I called my local (Marietta) Service Center to get an appointment on return, but I lost the phone signal before the call went through. When I arrived at Kingman the clunk went to a clunk-slip-whine-clank! I called Tesla and they suggested Phoenix might be an ideal detour. Scotsdale SC called me back and asked if I could make it there. I ALMOST did. About 20 miles away trying to make a right hand turn in traffic Flossie blew. No clunks. No clanks. Just a whirring slipping noise half way through a turn. Had to get out and push her to the curb. VERY Embarassing!!! She was flatbedded to the service center and the next morning I got a call the drive unit needed to be replaced. Four hours later I had a clean, quiet, fully capable Flossie returned and was on the road to the Grand Canyon. Flossie is vin 25619.
glhs272
Unnamed plug faced villian
Hmm... This is similar to the noise/behavior that my original drive unit was experiencing and Tesla decided to replace it when I took it in for it's annual. I was surprised actually. It seemed have a moderate whine or resonance at speeds 55 to 70 mph and low torque on the motor (5 to 20 kw). Seemed to me like it was just the way the gears "broke in" and was not going to fail or get significantly worse. It didn't bother or worry me enough to have Tesla look at it. It started do that after about 5000 miles and didn't really get much worse until they replaced it at 21,000 miles. The replacement drive unit has a different "feel" than the original unit ever had. It seems like the gears (different ring gear & pinion) are cut slightly differently. They mesh tighter and resonate at lower speeds and high torque where it is not noticeable. The result is it is absolutely silent at almost all speeds and especially the 55 to 70 mph speeds at low torque. Exactly where the original unit was loudest. I could be wrong because tesla never said what was actually wrong with the original drive unit and I didn't press them much on it. I have been happy with the replacement unit thus far at 27,000 miles.
Sounds like yours was replaced around the same time as mine. That was my 2nd replacement and (knock wood) so far so good. It is incredibly smooth and silent no matter what I do to it. I hit 90 MPH the other day on the freeway and couldn't believe it. There is no way that would have happened with my last drive unit, or even the original that came with the car. Last replacement came with updated motor mounts.
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