I have a single speed on a Silverado custom, the terrain mode applies some braking, but it is a poor 4lo mimic, kind of nasty of Chevy to do this, while not needed often but when u need it u need it. I don’t think a 4wd without a dual speed transfer case should be called 4 wheel drive but rather all wheel drive so that us customers looking for 4 wheel drive will get what we are looking for