Tail Rotor Lube
Here's a tip I'd like to share with you guys. If you come upon the oil in your Tail Rotor gearbox suddenly getting darker than normal, almost to the point of turning black try this before going out and looking for another gearbox. If you happen to have an overly eager A&P who might over-service the crosshead bearing, check this out. When the crosshead bearing gets over-lubed, with the bearing being enclosed (not open such as on the m/r system), all that grease has to go somewhere. What happens is, all that grease travels down through the output shaft and drops down into the gearbox, contaminating the oil. In addition to Huey II's, this also pertains to similar models. Hope this helps.