I recently ordered a new transmission hump to replace my old one. It came as bare metal smooth metal. I thoroughy cleaned the peice with PRE to insure it was clean. I then sprayed it with extreme chassis primer following directions on the can and sprayed two coats allowing 24 hrs between coats then waited another 24 hrs before topcoating with extreme chassis black. Problem is after a week the extreme chassis black can be easily scratched off. With all the great reviews I figure the problem was with my prep. Should I have sanded the bare metal to allow a better “grip” or does this paint just take a long time to fully cure? Any information would be great.