[svxistentialist]

Sludgy oil and bad colour probably points to O ring fix again as Kuoh suggests. This "cavitation" is bound to affect the oil, and it has been working for two and a half years.

Check also the rubber boots on the rack, you may have seals gone/going inside which would churn up the oil also.

You mentioned twice the fluid was a litle low. Where is it going? Must be escaping somewhere. Do the O-ring thing first.

Joe