Automatic Locking Differential Lubricants. [Note from Michael Asmussen, Torque Control Products Division of Eaton Corp.] We recommend the following lubrications for our 1041 automatic locking differentials: 1)Texaco 2276; Synthetic 75 W90; GM Part # 9986115 2)Texaco 9622; Mineral based 80W90; GM Part # 9985290 3)Texaco 2080; Synthetic 75W140 (heavy duty applications); GM part # 9985991 Note - All of the above lubes are preblended with friction modifier. No additional modifiers are necessary or recommended. As far as other lubes are concerned, any standard GL 5 lube will work, but the units perform optimally with the three listed above. [Comment from Castrol:] Thank you for contacting Castrol regarding Syntec 75W-90 GL-5 gear oil in your Volvo 1041 differentials with an Eaton Automatic Lock. You may use SYNTEC gear oil with full confidence. [Comment from Mobil:] Mobil 1 Synthetic Gear Lubricant meets the GL-3, GL-4 and GL-5 API ratings. If the manufacturer requires the use of a GL-4 rated lubricant ONLY, then you should not use Mobil 1 Synthetic Gear Lubricant.
