Just recently on my 2003 mazda 6 i4, I rebuilt the engine because first gear quit working. I did everything to the ATSG manual specifications and reassembled my car. After driving about 200 miles, I started to lose 3rd and 4th gear, but if the car sat for a couple hours they came back.

I than noticed it was leaking transmission oil from the belhousing at a drop a second, and after checking about 10m later, there was a oil spot roughly 2ft in diameter.

I believe the oil leak is the reason i lose 3rd and 4th after driving awhile due to the lack of hydrolic pressure in the transmission, but I'm confused on how its leaking and if I need to take the tranamission back out. All the oil pump seals were replaced along with the torque converter.