I found a couple oil spots on my driveway recently, so I looked under the car and found the culprit. It seems the seal between the transmission and driveshaft is the culprit, and I can only guess the leak looks like oil because the fluid is so old. Is it common for a 100k mile LS1 to leak at this point? I know it's not the engine, it's as dry as a bone, the only place the underbody has any fluid on it is right below the point the DS mounts into the tranny. Is there a seal there? If so, what's it called? And if anyone has any experience with this, what would be a fair price to pay for someone to fix it?

This is really bugging me because up until last week this car hadn't had the engine or transmission touched, and I'm not real thrilled with this leak. I'm afraid they'll pop open my transmission and tell me blah blah blah you should get it rebuilt for some reason or another.

 

If it is the rear tranny seal, just do it yourself. The seal is cheap, and it's not that hard.

Pull the driveshaft out (if you haven't drained the tranny fluid it will now come pouring out). Use a seal puller to pull the old seal out. Then carefully tap the new seal in around the edges until it sits flush with the tailhousing. Assembly is reverse of disassembly.