Just replaced my gearbox oil to the latest vw gear oil G0 70 726 A2 for golf 1.8t 02J gearbox , however after about 1000mls my 5th gear is whinning between 40-60 MLS PER HOUR and now 4th gear is also starting to whine slightly. Changed gear oil to improve my gearchanges which this latest oil did but didnt expect noisy box as well. What course of action can i take here as i did use genuine parts .