My car was leaking oil somewhere from the transmission. The oil appeared to be running off of the top of the transmission, down the case, and then forward where it dripped off of the bell housing. Originally I thought it was the rear main seal which I had very recently replaced, but careful inspection showed it was not. I bought the transmission cover gasket, the transmission to bell housing gasket, and the input shaft seal. I did not know exactly where the leak was coming from, and I wanted everything on hand.

I pulled the transmission, still not sure about where it was leaking. Then I stood it up on the bell housing end and wiped all of the surfaces off with a clean rag. I didn't have too long to wait before oil started appearing at the joint between the bell housing and the case. The top cover and the bell housing almost meet, but close visual inspection revealed the bell housing joint leaking. I set the transmission in a box with bell housing end up and removed the bell housing. The gasket came with the bell housing and it appeared to have been damaged at the time of original installation, as the top part was pushed down into the hole for the shifter shaft. It would be impossible for the gasket to fail this way in service, so it must have been a poor installation at time of assembly at the factory. I checked the clearance for the shim between the input bearing and the bell housing per the service manual, installed the shaft seal and re-assembled. No leaks.