@jimbotron235:
Why bother transcoding the AC-3 track at all? Keep the AC-3 track untouched and mux it to the final edit of your project.
The fps (frames per second) from the DVD—29.97fps—and the fps from the Blu Ray—23.976fps—are one in the same—both audio tracks will have the same duration.
If you didn’t change the speed of the AC-3 audio when you imported it to Premiere, then by all means, keep the audio you have in Premiere as a guide when you are editing–so long as your final edit is at the fps of 23.976.
When you export the video with that audio, mux the DVD’s AC-3 track to your edit. Compare the speed of both AAC and AC-3 tracks and see for yourself if they are sync’d properly.