The 3 gears are driver, driven, and idler gears.
The gears in a planetary gear system are the drive gear, ring gear, and planetary gear.
If you are asking about timing gears with a belt system, you have to line the timing marks up with the marks on the gears. If you want to know about chain gear alignment please re-ask with vehicle specifics and I can answer that also.
you turn the cam gear and the crank gear with a wrench until the lines on the pulleys/gears line up.
gear ratio can speed up a device or slow it down. The gears that make up the gear ratio can be used to go from small to bigger thru a series of gears and slow the drive down , say 30 to 1. Or start off with large gears going smaller and speed up the drive say 1 to 30.
your syncronizers in the transmission are worn out in 5th gear. there what make the gears line up in speed so you can change them smoothly
Usually a single part made up of a serious of Gears that mesh with various gears of main shaft
Broken gears. The differential or ring gear or pinion gears are broken.
you make a path from 1 big gear to the otheri hope this helped if not go on you-tube and look it up
High gear ratios, 273,373,340 Low ratios, any thing starting with the #4 and up is a low gear ratio. 410 411 456 488 556 and up.
An idler gear is a gear which connects two other gears so they will turn in the same direction. :)
The dot on the bottom gear goes straight up and the dot on the top gear points straight down when the timing chain and gears are installed correctly.
Changing gears is easy. All you have to do is push in the clutch and then up and over to third gear.