You used the words "fundamental design issue" and claim there aren't any. Yet, it seems like drive units are at least on their 17th revision. I can't speak to whatever is the most current, but it's clear that prior to the 17th revision, they developed noises and failed, and the former have happened repeatedly for some folks, all well short of 200K miles on a given DU.
Don't you think that Tesla attempted to resolve some of these by redesigning something(s)? A proper resolution to a "fundamental design issue" is to redesign something (vs. a band aid).
From
The latest drive unit explanation, I learned of "Elon also stated that they have changed their internal goal from a 200,000 mile drive unit to a million mile drive unit." When we (or at least I) have known of none that have lasted 200K miles, and when there are folks who have only made it no more than 10K to 20K miles on a drive unit, sometimes repeatedly, you somehow have knowledge that there's no "fundamental design issue"?
Funny enough, in the above thread, I noticed a picture at
The latest drive unit explanation - Page 3 where they were clearly design changes between some newer version vs. older version. You also got me wondering and digging.
These also point to larger splines and redesigns:
When will there be Zero drive-unit issues/replacements? - Page 2
When will there be Zero drive-unit issues/replacements? - Page 4
I think these folks would also disagree w/your assertion:
Drive Unit Replacement Poll - Page 11
[Resolved] My P85 has developed the milling noise and Tesla won't fix it. - Page 12
[Resolved] My P85 has developed the milling noise and Tesla won't fix it. - Page 11
[Resolved] My P85 has developed the milling noise and Tesla won't fix it. - Page 13
I think it's very important to come as close as possible to comparing apples to apples here. In the world of ICE cars, we say you had an engine failure when the engine is in such bad condition that the car is not derivable at all or is in serious failure mode. These conditions would include a cracked block, a cylinder coming through the hood, and/or the car having an engine fire. Removing an engine from an ICE car is a major job for most cars and it is only done as a last resort when there is no other alternative.
If the engine develops an oil leak, a fouled plug, a noisy valve, or even a blown head gasket (especially caught early and taken to the shop when it starts), anyone who says the engine has "failed" would be considered a hypochondriac. On most cars all these problems can be fixed leaving the engine block in the car and replacing parts connected to the block. The same goes for other accessories like the starter, alternator, exhaust manifold, spark plugs, injectors (or corroborator), and many other parts.
So if we don't called a fouled spark plug on an ICE a "failure" how is the milling noise on a Tesla suddenly a "failure"? Just like the fouled plug, it needs to be fixed, but you aren't stranded on the side of the road because of the milling sound. I haven't heard of anyone's drive unit that developed a milling sound had it lead to the drive unit stopping working if they didn't run right into Tesla. Someone may have had a failure as a result of letting it go too long, but I haven't heard of it happening. Bad things can happen to an ICE if you leave some minor problems go too long without attention too.
There are two reasons Tesla replaced a lot of the drive units that had relatively minor problems:
1) Especially early on they wanted to do forensic analysis to figure out what was causing the problem.
2) Because the drive unit is an entire assembly and much simpler to remove than an ICE engine, it's sometimes quicker, easier, and ultimately cheaper to simply replace a drive unit that has problems that would result in much more minor sounding repairs on an ICE.
By the definition of drive failure used by people on this forum, my 1992 Buick had an engine failure 20 years ago, though I'm still driving on the same engine. It started leaking a little oil when it was a couple of years old (I seem to recall it was right after it went out of warranty). It never got any worse and was more trouble to fix than it was worth, so I threw some cardboard down on the garage floor and made a habit of checking the oil a couple of times between oil changes. It's never down more than 1/2 a quart between changes and it's been consistent for two decades, so I'm not too worried. So should I be screaming to GM about the engine failure on my Buick?
From reading the forum here, there have been a couple of cases of actual drive unit failure: ie the equivalent sort of condition we would call an engine failure in an ICE. The milling noise has been the worst problem I've seen. At least minor cases of milling are probably noticed more in Teslas because the car is overall so much quieter than an ICE. After reading a noise thread here about Teslas that included mention of the milling noise as well as other rattles and squeaks, I started really listening to the noises my car made. I also listened to the noises my SO's fairly new Subaru Impreza made. Both cars make an incredible number of rattles and squeaks. My car is overall quieter than hers, but there were still many noises I just tuned out because you expect ICEs to make various noises.
I remember about 15 years ago I had to get the catalytic converter replaced and the new one was bigger and resonated more than the old one. I'm sure it still makes that sound, but I couldn't tell you what it is now. I've been hearing it for 15 years and it's become part of the background.
I have heard recordings of the milling sound on some Teslas and when the problem is advanced, it can sound quite loud. Note I said "minor cases" of milling sound.
I know I'll get teased by the old hands for asking this, but can we please come up with some sort of distinction between a drive unit problem and a drive unit failure? Just because Tesla chose to replace the drive unit does not mean it failed, it just means the problem was such that it was cheaper and easier to replace it than to do some kind of on vehicle repair.
