I've decided to have a go at installing firstly my truetrac then if all goes well my detroit in the Disco. After a bit of research I'm still unclear on a few points. Some say that it is necessary to measure crown wheel run out, backlash/preload and then use the blue goo to check teeth contact. Others say run out and backlash/preload only. And then there are some that say just the backlash/preload is necessary. What is necessary? Any advice and tips appreciated.

Cheers,
Pete