I just completed rebuilding my 72c velvet drive. The rebuild replaced the seals and rings only. I took it back out on the lake and it was slipping when I tried to go forward. When I tried reverse it also slipped. After I shut the engine down and restarted, it went forward only in forward, neutral and reverse. I understand that something failed. I removed the transmission and it now spins freely in neutral. Does this should like an issue with oil pressure. I plan on taking it apart and doing an inspection. Any ideas?