They do not engineer any of that stuff. They just say it must do A B C and D under certain certain conditions. The stuff goes out for bid, lowest bidder wins most of the time.
Sorry, you're mostly wrong. And the lowest bidder doesn't always win or even win most of the time.
For drivetrain parts I find that doubtful. Either they design it themselves or they are very involved in the design and test process that the manufacturer goes through.
This is much closer to what happens in most industries...speaking from experience in the bearing industry (Timken/Torrington).
Company puts a proposal forth for a new bearing...design, specs, function, etc. The engineers show up with blueprints, requirement sheets, etc.
We make test runs of new bearing and send out test samples. Company's engineers come back with "These work" or "These changes need to be made".
Changes made, many times with the company's engineers in our plant looking at our process and making suggestions.
Final samples made and accepted, contract let. Full production commences. Ongoing QC goes onward...improvements happen during production, etc.
The upshot is the company, be it Honda, Toyota, GM, Ford, Caterpillar, Hoover, whoever, has a specific bearing needed in a specific application and has specs and designs drawn up for it well before the bids are put out.
Now, this doesn't mean an off-the-shelf or already in production unit won't work, but many times it is a "custom" job, as most are. So, the engineers at the car/whatever company already have designed what they want out of the part and we work within those design parameters to produce what they want with the way we make our product. What gets produced isn't exactly like what Honda/Toyota/etc. envisioned, but then again, it isn't exactly like what we'd design from scratch, either.
It's all compromise.
