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6th drive unit replacement and more
- Thread starter David99
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- Driving Dynamics Model S
I just read blog / article about a Finnish model S taxi. Apparently it had it's "back sledge" (big element that holds back wheels in place) changed. It sounds similar to your fishtailing. I'm not sure if that's helpful at all or if that's even the same thing but wanted to say if it might help you.
Wait, what? You want the owner to take a massive financial loss in order to address a defect?
The car pulling to one side or another isn't really "fishtailing", is it? What you describe sounds more like pulling, and it sounds like it is alignment-based. If everything is fine after you leave service and the problem comes back after 3 weeks, my bet is that your alignment is drifting. What you describe also sounds more like FWD torque steer, but since vehicle is RWD there must be some other dynamic at work.
Also, my car with 19" wheels tends to follow any deformations or imperfections in the road surface. I have significant tramlining issues on some roads with my 2013 Model S, especially when the car is in "low" mode. I have confirmed the same issues with multiple loaners, so it seems to be a common issue.
Also, my car with 19" wheels tends to follow any deformations or imperfections in the road surface. I have significant tramlining issues on some roads with my 2013 Model S, especially when the car is in "low" mode. I have confirmed the same issues with multiple loaners, so it seems to be a common issue.
mknox
Well-Known Member
I'm in the same boat. On my third DU and still experiencing problems in spite of several attempts to fix.What I don't understand is how a new revision DU can give me problems like this, but new cars with presumably the same DU are okay.
If it's pulling to one side under torque, it's likely a loose link on the rear suspension. My wife's car had a loose integral link. I took it to a trusted independent alignment shop and they located the loose bolt. The suspension was re-ligned and loctite applied to all the fasteners. Problem solved.
Yes that's exactly what they have been doing 5 times now. Fixing the suspension and alignment. And 5 times it came back so there is a more fundamental issue.
Nope. I said asking Tesla to give him a special deal (or good trade-in deal) to get back the car. So he WON'T take any financial loss.
The only thing I can think of that causes drive units to go bad is something amiss in the car chassis' electrical ground. It's obviously something specific to the car itself because the same cars have repeated drive unit problems while other cars built at the same time have no problems.
Service center said they are at a loss and forwarded everything to the regional manager. Hopefully that will lead to a solution.
mknox
Well-Known Member
Mine is definately mechanical in nature. You can feel it in the seat of your pants when it "clunks" going from acceleration to re-gen and back.
I think you've said it gets better for a while when they do a drive unit change. I'm talking about the root cause that is leading good drive units to go bad. If current is flowing where it isn't supposed to, that can cause erosion of the metal parts which will lead to mechanical problems as those parts wear abnormally.
If there are small arcs between metal parts that have a tiny air gap between them, the metal on both sides will be eaten away by the arc over time. In dry air, it takes 24,000 V to jump an inch, but 400V will jump a 1/2 mm gap. And you're dealing with very high currents. A large arc will leave the metal scorched, but a small arc will just eat away the metal and leave little trace there was an arc.
>maybe there is an issue with the car itself [David99]
I see a test harness with at least a dozen legs, each with a milliammeter, for connecting to critical grounding junctions throughout the vehicle. But then of course handed to a weekly hire “here, run this test”.
>It is not a "grounding issue". Mechanical systems involve tolerances. The tolerances describe the apparent randomness. [Ingineer}
Bearings (ball or roller) pit under current flow. Why are you taking this off the table?
>The only other mechanical connections are the 2 half-shafts equipped with CV joints that allow flexing. [Ingineer]
but do NOT allow axial movement.
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I see a test harness with at least a dozen legs, each with a milliammeter, for connecting to critical grounding junctions throughout the vehicle. But then of course handed to a weekly hire “here, run this test”.
>It is not a "grounding issue". Mechanical systems involve tolerances. The tolerances describe the apparent randomness. [Ingineer}
Bearings (ball or roller) pit under current flow. Why are you taking this off the table?
>The only other mechanical connections are the 2 half-shafts equipped with CV joints that allow flexing. [Ingineer]
but do NOT allow axial movement.
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I would not accept that, keep pushing and go higher up if necessary. You paid a lot of money for a premium sedan, more importantly a silent EV. Show them their own website where they clearly advertise it.
mknox
Well-Known Member
Well, in my case the clunk-clunk noise was back in a matter of days after the DU replacement, and within probably less than 100 miles. I'm not sure I buy the arcing argument here. They will do something with the wheel hubs, not the DU itself, and the noise does go away, but will return in a matter of days and gradually get worse until I take it back in.
I've seen a lot of people report the noise goes away for months. It sounds like whatever is causing your problem is a bit different from the norm.
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