Hello, my brother drives the same vehicle as me. But he can be switched harder, just when the vehicle is cold. He has now 160tkm down and probably the transmission oil has never been replaced. I drove the Opel F28 6-speed gearbox with my Kadett Turbo and Calibra Turbo at that time. There I also had the problem that he could be switched cold rather hard. In the LET forum Castrol SMX-S was recommended to me at that time as transmission oil. After changing the F28 transmissions BUTTERWEICH could be switched! There he was cold better switchable than before warm with the old oil! My question, what do you take with the Omega B switch? If I can believe opel-infos.de so have F28 and R28 (what I and my brother drive) both a transmission oil of the specification “SAE 75W-85 API GL4”. So I would buy now 2 liters of the Castrol SMX-S (means differently by now: http://www.amazon.de/…/B005K95XL2) and fill in. Or there are better recommendations for the HAD oil, but for the same as well as well as well as well as for the HAIR-D oil.