Red Line 50304-6PK Manual Transmission (MT) 90W Gear Oil - 1 Quart, (Pack of 6) 75W90 GL-4 gear oil (similar to SAE 5W40/10W40 engine oil viscosity) Popular in Nissan, Mazda, Mitsubishi, VW/Audi, Lotus Elise/Exige, Toyota Offers quicker shifts, perfect synchronizer coefficient of friction Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage High performance gear protection and longer synchro life