ARO Help Please

My LP12 (ARO, Armageddon) was sounding rather bright over the weekend so I decided to check my setup. The pillar assembly was coated with oil that made it's way down collar hole effectively coupling the pillar to the collar. I cleaned off the oil and set everything up again and it seems to sound OK. Does anyone have an idea what the problem might be? Is the oil coming from the pillar assembly or possibly something else? Assuming it's a problem what needs to be done? And who can do the work?

Thanks
John