There were two seals available at the auto parts store; a black one and a red one. My 620 came with a black transmission seal, but I purchased both to compare the new ones to the old one.
Here is a picture of the two new seals on top of their respective boxes. The old seal is without a box.
Here is a picture showing the thickness of the seals:
I had installed the red seal even though the black seal was installed. I thought the red seal was OK to use because it still fit, but I was wrong. I had not seen the black seal at the auto parts store and was not aware it was available. When I went back to the store to fix the leaking newer seal, I found the red and the black seals available. I purchased both and luckily I was able to compare the original seal to the two seals that I purchased. I removed the red seal that I had installed and I installed the black seal shown on the picture. I assume that this will keep the output shaft from leaking, but it is no warranty.
These pictures are of the seals next to each other:
