I’ve had a FL chassis new since 2005. Great service, great support.
So no chassis mfr make all of the components. The trans is Allison, the engine is CAT or Cummins, airbags, rear end ,brakes, filters, air systems are all sourced from third parties.
FL makes different levels of chassis. Entry level is solid front axle, drum brakes, etc to high end independent front suspension with disc brakes and big engines.
The FL factory service center in Gaffney SC is a joy to deal with and I won’t use anyone else if I can get there
I’m not a huge fan of your local semi truck centric Freightliner service centers. They are competent but a tad expensive and not thorough.
Buy with confidence.