9" posi question

[69MyWay]

I have a 9" in my 69 Camaro. I am running standard rear gear oil and the POSI additive.

Problem is, the clutch in the posi unit is WAY too aggressive and it binds/catches very strong in slow speed turning. It makes the back of the car feel like it is going to tear off.

Question is - if the clutch is too aggressive, can I tone it down by changing fluid and NOT adding posi lube? Correct me if I'm wrong, but doesn't the posi lube help the posi clutch get friction - or is it the other way around?