98 DX Hatchback
250k
5spd

So I just bolted up an 01 EX tranny to my 98 DX hatch. While I was in there I replaced the clutch and rear main seal. Now 600 miles later I am noticing a fresh oil leak from the bottom of the tranny. The transmission was bone dry when i installed it and the car did not leak fresh oil before the install.

I pulled off the exhaust and dust covers to get a better look. There is fresh oil on the oil pan, bottom of tranny, dust covers and it's hard to see but also relatively fresh oil inside the the tranny all around the fly wheel. Curiously not much but a light haze on the back of the flywheel itself.

So I cleaned it all up as best I could and drove around the neighborhood until it reached normal operating temp. Took a second look and I see oil on the bottom edge of the oil pan (below center of fly wheel) and can trace it up to where the oil pan curves around to fit nice and snug next to the fly wheel/rear main. I did redo the liquid seal on the oil pan 4 years ago. There was also oil on the bottom edge of the transmission where normally the dust cover would sit.

Did I botch the rear main seal replacement?

 

Maybe the spring on the rear main seal popped out during installation???

You said the trans was bone-dry so I'm ruling out the input shaft seal on the transmission...

Good luck man. I feel your pain.