Usually when people say that they have no audio when they preview, it's because they're hitting the spacebar (using standard preview) and not using RAM preview. Check to make sure that you're using
RAM preview.
If you still have no audio, check to see what happens when you do
an audio-only preview.
Regarding audio on output, make sure that
Audio Output is selected in the output module.
---------------------------------------------------------------------------------------------------------
Todd Kopriva, Adobe Systems Incorporated
putting the 'T' back in 'RTFM' :
After Effects Help on the Web
---------------------------------------------------------------------------------------------------------
If a page of After Effects Help answers your question, please consider rating it. If you have a tip, technique, or link to share---or if there is something that you'd like to see added or improved---please leave a comment.