this car has been driving me crazy, cant find a trans for it and anybody that sells me one is trying to hussle me.....so im thinking to fix the transmission myself. the reverse gear is bad, every time i put it in reverse it makes a grinding noise but all other gears are fine...where can I find a transmission parts store or website where they sell parts for trannys. any tips and help would be greatly apprectiated!

4 door Honda accord 2.2 vtec automatic ex.