I don't know what specs were used for oil pressure, but the spec in the manual isn't enough. If I don't see 140 PSI at 5000 RPM, even more when the engine is cold, I would suspect the oil pump. Also, you can inspect the relief valve within the oil pump. Remove the plunger and inspect it and the bore for scoring, it'll probably show a sign if it's been sticking...which is the problem they had with those pumps. Based on your description a bad tranny is more likely. There is a bench test from Honda tech services that's not in the shop manual, although it can be a little tricky and take a bit of experience to interpret it. Hold the output end of it, while turning the input end...do this throughout the whole range of the swashplate. If at any point the tranny locks up and you can't hold the output end from turning with the input, the tranny's junk. Please note, you may feel a slight sensation of the output wanting to turn, but it's only a sure thing if the two actually lock up. Also note, don't assume the tranny is bad based on the fact you hear a slight noise, or it doesn't turn over perfectly smooth. That's normal and a new one will feel the same. Hope that helps.