2016 Freightliner Cascadia Evolution Automated Manual Transmission Help

So I have been driving a brand new 2016 Freightliner Cascadia Evolution Automated Manual Transmission truck at my work.

No stick shift or foot clutch pedal.

I've noticed when I go down a grade (Eisenhower or Vail or the other grades heading down towards Denver on I-70), I push the M in to go to Manual Mode (by pushing in on the end of the stick towards the steering wheel) and select the gear I want and put the truck with the jakes on low, but after a few minutes, it starts upshifting on its own even though I'm in Manual Mode, and then of course the truck starts gaining speed and momentum. Thankfully this happened on dry pavement and clear weather conditions. I can only imagine the panic I'd have felt had this been on a snowy or icepacked grade. I'm used to driving a conventional stick shift and clutch manual transmission.



I've poured over the manual and I can't find anything that relates to my issue.
https://secure.freightliner.com/new...er's Manuals/new cascadia driver's manual.pdf

and this bulletin as well.

http://cooperfreight.com/clientimages/57483/employee/weather dd12.pdf
(Against all of my instincts, page 9 of this bulletin says not to use the jakes when descending a grade....?)


I've read the manual and the inclement driving bulletin I linked above and I can't find anything in there about why it would start shifting on its own despite being in manual mode.

Is there something I'm missing? Does it require some sort of specific programming?

Hoping someone with experience can clear this up for me because I am lost and confused here.

 

Well that's what my trucking instincts tell me, but that bulletin suggests otherwise and it's throwing me for a loop.

If I leave it in automatic mode, I start picking up too much speed and momentum going down the grade and it tries to keep upshifting to the highest gear. It makes no sense to me.

 

well that's interesting. this truck had no miles on when I got it, and I work for a contractor. Wonder if they set it like that specifically? Or if it came that way from the dealership?

 

I've never been so angry while driving a truck as I was when I drove this overpriced bucket of bolts.