Hey there!
My strap gave up today, resulting in my Nikkor 80-200 2.8 ED hit the asphalt lens first, pushed by an D300 with batterypack. Pretty hard...
Im glad I had a heavy UV filter on. But would have been even happier if the sun-cap had been on.
I cleaned off the broken glass and tried unscrewing the filter, without success cause the lens was squeezed slightly oval

It seemed to work though for awhile, till I tried a closeup zoom where it jammed

. I used it manually for a few hours and tried the AF again. IT WORKED!!, the whole way

Thats quality...
And check your old strap. I had a neoprene one with small fake leather pieces that just gave up. I could easily rip the ok looking side off when I tried. Dont use fake materials . And do a pressure test now and then...