The cruise control on my 2014 Holden Cruze drops down to fourth gear while driving, but if you put it into manual and change up to fifth gear it climbs the hill without labouring or pinging, but increases speed. If you drive the same hills just in auto it behaves as you would expect. When you go up a very steep hill it drops down to fourth gear as you expect. I havfce spoken a few other Cruze owners and their Cruze does the same as mine. My son who is a qualified mechanic said, there must be a calibration problem with the cruise control. What do you think?
That would seem to be the way it’s calibrated, but is it a problem? I don’t think so; it’s just a quirk of the way it works.