Jaymanbikes

I have a 1977 280z with a 5sp with 75k miles. The car sat up for approx 10 years, I purchased it approx 6 months ago and got her up and running. The clutch was slipping and had what I thought was a slight throw out bearing rattle. I had a shop replace the clutch, throw bear bearing and I also had them put a new resurfaced stock flywheel. Within a week or so I have got a rattle that goes away when the clutch is engaged. I can also hear it as I am in lower gears moving but seems to go away as I get into 3 and 4th. The Trans shifts very smoothly. It was suggested that I replace the Trans Lube to a Redline oil. I wasn't able to get it locally so I used a Mobile 1 product. After the change I didn't notice any improvement. Looking for suggestions as to next logical step. Would it be worth ordering the Redline oil and giving it a try. After reading some of the threads my thought it that it is the input/pilot bearing? I appreaciate any suggestions and or thoughts!