Our T-590 with 1700 hrs had a roller (intermediate) that started screeching. I replaced it with a new one and like I do with most broken things have taken it apart to see what went wrong. to my surprise, it has 2 bronze bushings instead of bearings as I was expecting. Sealing is done by 2 large o-rings. things don't look worn but the unit is dry. There is a plug (1/8th NPT) I want to rebuild as a spare. Does anyone know what type of oil is used in them? Gotta try it! Thanks for the input, Andy