Mine definitely engages at some times but not others. I've driven a manual transmission for decades so it is easy to notice when it works (but not so obvious when it doesn't). It has worked in both directions (backing up when pointed down hill and going forward uphill). I've noticed there seems to be some minimum stop time before it engages, since I can stop momentarily and intentionally roll back into a parking place without shifting into reverse. When I start up the car in same parking space, it does not engage and I will roll backwards when pulling out. Still not sure about the degree