IPod Classic 120GB won't sync songs

My iPod recently began having issues, such as not playing songs that should've worked, skipping over them, etc. So I chose to restore it, and now it stops syncing songs at around 3 GB worth of music, and I'll either get error 1303, 53, or 69. I sync manually, no photos or anything besides music. When it gets to around 3GB full, the sync will start going really slow, and I can hear a weird crackling sound coming from my iPod, as if it's trying too hard, and then the error message pops up after this goes on for a while.
Here's what I've tried so far:

- 5 R's
- Disk Mode
- Turning off UAC
- Using the Administrator as the account doing the sync
- Using different usb cable
- Using different USB ports
- Using different laptop/desktop
- Updating Itunes, Ipod, & Windows Updates

Everytime I see a "solution" in a thread, I try it, and not one of them has worked. I've also heard it is a hard drive issue, relating to Itunes 9.0.3, which I've been using. http://discussions.apple.com/thread.jspa?threadID=2298386&tstart=15

If nobody has an answer, at least can someone tell me how to convince Apple to send me a replacement? My iPod is still under coverage of the warranty.