I just bought a 79 Z that has a T-5 5 speed. It has a leak around the speedo cable. Does the cable require a gasket? Generally, is it simply a matter of tightening it? Is there any plastic at the end/inside that might have broken?

Thanks, not real familiar and this is my first camaro.

 

That's a common leak spot. The part that the cable mounts to is a small aluminum housing. The shaft of the driven speedo gear spins inside the housing and the whole assembly slips into the side hole of the trans tail. Either one of your o-rings are bad, or the housing is worn and sloppy where it fits the trans, or both. The one on my trans would be fine unless the car sat for a week or two, then it would leak. The aluminum gear housing was worn and a sloppy fit. So I found a real well made replacement steel housing on ebay, and it's never leaked since.

 

I would just replace the cable. There are not orings in there, and overtightening will sometimes cause the issue.

 

There ARE o-rings on the speedo gear housing, which is what I was describing. It's a common spot for a trans leak. The cable housing doesn't have trans fluid inside it, so the cable isn't the source of the leak.