So I've had my 94 3000gt SL for about 3 years now and I've recently re sealed my engine and had my transmission swapped out. When I put my engine back in and installed the trans, I took it out for a test drive and my oil pressure dropped down to zero and shortly after my engine started to knock. I also noticed that when ever my transmission hit 3rd gear it would just stall my engine out. I would have to rev my car to keep my engine alive and keep in mind its an automatic. So now im stuck, I turn the engine and it just knocks louder and louder now. I don't know what is going on with it. Im thinking maybe it is just the oil pump. So does anyone knows what going?