This is strictly my interpretation of this song. I do not hear any 3rd being play during the Piano/Bass lines throughout the song. The chords I wrote for the Guitar line that follows are played as two notes each starting on the 3rd and 5th of the chords respectively moving down to the root and 3rd. I found that this worked better when using the instrument playback track.

Rikki Don't Lose That Number - Steely Dan (1)

1. Rikki Don't Lose That Number - Steely Dan