How much would it cost to fix transmission leak

What is your question?

158,000 miles. Just noticed today there was a puddle of reddish looking liquid under car. I just had the valve cover gaskets replaced to fix an oil leak last month. That cost me $874. (Included oil change of course)

What makes this problem better or worse?

Not sure

How long has your 1999 Mercedes-Benz E430 had this problem?

Just noticed it after I went to the grocery and back. Went out to get the car washed and as I backed out I saw the puddle on the pavement