Ground My Gears !!!

[bmwcoupedriver]

This is the first time... I have never done this before.
Stopped at a light on a hill in San Francisco.
The guy in front of me starts to roll backwards towards me.
I panic, try to quickly shift to reverse and in the process, I don't depress the clutch as much as I should.
The result: a horrible grinding sound.
As I said, I have never done this before. Any ideas regarding how much damage I could have done ?

Joseph

 

[Kirby]

Assuming you didn't grind it for 2 or 3 minutes you did little to no damage. If it happens once or twice a year, the transmission will fail due to something else long before the gear grinding affects it.

FWIW, it isn't actually the gear mating surfaces that grind. It's the engagement pins called "dogs" or "dog teeth" that are spinning too rapidly to slip into their holes in the actual gear.

If you're curious, see more info:
http://auto.howstuffworks.com/transmission3.htm