This is happen by accident. I have this slope in front of my garage, while i was waiting for the garage door to open, i engage the tranny into N, then somehow i forgot to shift into D, the car roll back and as i shift back into D the car jerk once and the engine died. The jerk is quite noticeable. I don't recomend people doing this though, it may kill your gearbox.

Is this quite normal, or something wrong with my gearbox?? The slope is pretty steep.

 

this may in fact have been a safety measure designed to keep you from breaking something. the manual says somewhere that you are not supposed to shift from neutral to gear unless you're near idle. but the stall could be there to keep the tranny from breaking. or whatever else might break from going one direction and shifting gears to opposite, while not stopped.

 

I wouldn't worry about it W, as long as it is still driving the same. If there's any noticable difference take it to the dealer.

I've yanked the car into drive while rolling backwards heaps of times on my other cars (although I wouldn't advise it).