Ford suggests to use WSD-M2C200-C specs oil which is a 75W-90 oil. I searched up the internet for information and as a result I found people who say WSS-M2C200-D2 (75W FE) could be a better option, since it's a thinner oil and MTX-75 runs better especially on cold temperature. My only problem is that I can't found any official source that would confirm it won't damage the gearbox. What's your opinion? My car is a 2006 Ford Focus 1.6 TDCi