I looked up the part number in my 88' parts catalog and it lists two part numbers for the top and bottom. the bottom is MB309651 and the top half is MB309653 and it is definitely a different than the one piece unit used on the manual trans. however when i look them up at napa's website they are listed as the same part. I guess the parts suppliers have the wrong listings for parts and think it is the same thing when it isn't? maybe they sent you a manual trans mount?