Looks like the 1st model of the Penn 320 GTI. The newer ones have an all metal level wind hood, while the older model had the graphite one like yours. At the very least, it will need a level wind and a pawl. You may need a new drive gear, but that is not always the case.
Here is how to fix it:
1. Remove the nut on the bottom of the levelwind that hold the pawl in place.
2. Remove the pawl.
3. Take the right side plate off and remove the small nut on the end of the level wind. 4. Now remove the left side plate and slip out the level wind.
5. Make sure the gear on the right side of the spool, and the gear that turns the level wind are OK.
6. Give everything inside the reel a good dose of Corrosion-X while you have it open.
7. Replace the levelwind, pawl, and ressemble.
Parts should be less than $10.
The first model (the one you have) was a little better reel, than the next generation, in my opinion.