I changed my oils to Miller's TRX Synth 75w-90 and the gear change is now a lot worse than with the old crappy oil. At times, it can't even get into gear while stationary. Gets slightly better when the car warms up. What is better full synth oil to use? Or just this MT75 oil https://www.opieoils.co.uk/p-147606-...ion-fluid.aspx has anyone tried it?