Penrite Outback Hardened 4x4 Gear Oil 80W-90 is a mineral based, multipurpose gear oil formulated with an OUTBACK HARDENED additives package suitable for use in differentials, both limited slip and conventional as well as manual transmissions that require API GL-5/6 specification fluids. Penrite Outback Hardened Gear Oil is specially formulated with non-aggressive extreme pressure additives to provide maximum oil film strength for increased protection, ideal for use in applications that are prone to high shock and heavy loads. The premium mineral base oils provide superior thermal stability while also maintaining cleanliness and reducing abrasive wear extending the oil drain interval. Penrite 80W-90 also contains the correct amount of Limslip additive for use in limited slip differentials therefore, requiring no extra additives. To find the manual transmission or diff oil suggested for your vehicle; either add your vehicle to My Garage or check with your manufacturer, vehicle user manual, your local mechanic or head in-store and talk to one of our friendly team.