juneoliver

Syncing 4-track To Pro Tools

I'm trying to transfer some tracks from a cassette 4-track to pro tools Free on a Mac running OS 9.2. I'm trying to do this as simply as possible without buying more gear. My method has been to record a bar of a kick drum at the beginning of each track on tape. Then I record each track individually from the 4-track to the mac throught the sound input jack. Once all the tracks are in pro tools, I visually line up the kick drums at the beginning. The bass and drums sync up fine but the guitar starts to go out of sync by the end of the song. I thought everything would sync if they started from the same point. Is it possible Pro Tools is dropping samples or something like that during the recording process? Does anyone know why it's not syncing or have a better way to do this?

thanks for any help you can offer
June