Did you ever have the fluid changed??? If not and you have a bunch of miles, and your friend was hot-doggin it...he may have screwed up your tranny...Read my post https://www.honda-acura.net/forums/s...97#post3158297 about the SS tranny. Actually reverse not working is one of the first signs your trannies goin out.

BTW, if you have it changed, drain and fill, flushing will probably ruin it for sure.