I also had a good seal on the pan and did not want to touch it. I trimmed on the cover the area that Don is talking about, and it helped, but could not get the cover on with a new pan seal. I tried with the old seal and a little rtv, but could still not get it on. I removed the pan seal and got that area of the cover clean and dry. Also cleaned the front of the pan really good. Brake clean or aerosol carb clean. I installed the cover with no seal. I got a fresh tube of Permatex Ultra Black and squeezed it into the seal area making sure it went in as far as possible. I let it set overnight and it turned out good, no leak. I have done that twice within the last 2 years, success both times. "Right Stuff" is another good product, but it was not available locally.
Been there,done that!!