You make it sound like they're changing companies like I change underwear(ever couple yrs!
). More than likely they have a long-term contract with a 'trusted vendor' which has known quality and can supply a lot of fluids and lubes. That's generally how automotive contracts work. I've worked with a number of plant managers of companies who were OEM manufacturers for just about all the major car companies (doing engineering/contracting work). I've had plenty of earful's about auto contracts over the years.
Yes the contracts go out for bids now and then, and the vendor is under pressure to keep their numbers very competitive, but the tusted incumbent vendor (who is in
good standing - key phrase there) generally gets 'last-look'. Or even the Car company tells them kind of where they need to be, money-wise. And if you have a nice big contract, as a vendor you DON'T want to lose a big chunk of revenue, and you do what it takes to keep it. Yer beholden to shareholders or the company board to meet revenue targets. Where would you go to pick up a multi-million dollar steady contract? So you do whatever it takes to keep it the bid. There's usually a bit of back and fourth and push-back on both sides to end up with what they feel is the best price. If all works right, the car company gets a better price and can stick with their trusted (preferred vendor) ...for a LONG time my guess is. And even so, Chrysler has a spec out on ever fluid that needs to be met.
So it's not like the car companies are changing fluid companies all the time. That wouldn't make a lot of sense. They would have to go and re-test (verify) a new vendor's lubes meet spec. Thats costly extra work. A vendor also needs to have the capacity and ability to understand and be ok with payment terms. Maybe integrate with the auto mfgrs software, be able to meet delivery targets, perhaps on a global scale (or pay a penalty), and a host of other things that go beyond bottom dollar price. It wouldn't do the car company any good to go with Ka-boing-Lubricants Inc ...a mom and pop company in shang-dang, then in 6 months change to Ker-Pow-Fluid Technologies, nestled between bamboo huts in the jungles of Laos ....because they were .005 cents cheaper. They probably wont be able to deliver on time or run into quality issues. Pretty soon you have a cluster-screw of who's supplying what..
They (Mopar) probably stick to the same vendor as much as they can, and it would need to meet spec anyway.
.