This is a combination of Fast Track Mechanic videos and videos created by other you tubers. The problem on you tube is knowing which videos are good and which ones are teaching you bad practices.
I have done all the hard work for you. I have dug out the nugget of gold or particular lesson in each video. Now you don’t have to watch 3 minutes of video to get 30 seconds of gold. The video starts and stops at the relevant points

Little and often is the key to learning. If you want to hit the workshop floor running like and follow the Truck Mechanic Lesson a Day Facebook page and a lesson will pop up in your news feed daily. They are in a random order so it doesn’t matter when you start watching.
Lesson a Day Facebook Page

More technical in depth videos
EngineDrive TrainBrakesAdvanced Electrical